I notice that my ethics, my morality, my beliefs, differ in many ways from those of the past; I expect these things to differ in many ways from my own, in the future.  I notice the relationship between these two concepts is reciprocal.

My grandfather talked to me, several times, about how he knew I had my own life, and that I wouldn't always want to spend a lot of time with him; he was explicitly giving me permission, I think, to do something that he himself regretted in his youth, but understood better with age.  He was telling me to live unfettered by that particular obligation.  I didn't see him much after I started working, and then he passed away.

If I have grandchildren some day, I know what I will tell them.

I consider the alternative grandfather who I didn't have, who was jealous of my time and attention, and how it would have changed things.

What do we owe the future?

I think maybe we owe the future the freedom to choose for themselves, unfettered by the chains of our expectations.  The freedom to choose means nothing if it does not include the freedom to make what we think are the wrong choices.  The conservationist wanted to restrain the choices of the future, to limit them.  And while I think the cuteness-maximizers are wrong, we owe them the right to be wrong, just as we act in so many ways our ancestors would have regarded as wrong.

The idea of a god-AI enshrining some particular group of people's values forever doesn't look very appealing to me; indeed, it looks like an abdication of our fundamental responsibility to the future.

What do I owe the past, therefore?

Gratitude, that I have more choices than they did.

I wasn't expecting to based on the title, but I like this. I think it's important to be able to hold commitments in mind for your future self. But it's also important, when trying to hold your future self to something, to be conservative about what you commit to so you don't screw up your ability to make these commitments in the future.

I can think of several times when I explicitly tried to ... do something like acausal trade ... with my future self.

1. When I was about 9 years old, I had a very complex set of relationships with other kids, including some kind of "war" and an on/off relationship with a specific boy. I remember thinking to myself, "Usually, when people are adults, they think this kind of thing that kids do is stupid. But future me, you'd better not do that. Think of this as important. This is really important to me."
2. When I was deciding which college to go to, I attended a weekend at one of the places I was accepted that they held to attract students. I really enjoyed it, but the college was extremely expensive. I thought, "Hey, future self... I don't want to hold you to this, but listen, this is REALLY nice. I know it's expensive, but seriously try to work out if there is any way you can go here, for real."
3. When I was giving birth (recently), I thought, "You know, I've been planning to do this again, but holy shit, it sucks. Future self, seriously consider whether this is actually worth it."

I'm shaping up to ~violate the commitment in all 3 cases, but I think there are good reasons that past-me would accept if they knew.

1: I don't find it that important in retrospect, but it's not because I was "only a child" at the time; it's because basically all things in life recede in importance when they happened to you a long time ago and you don't interact with the relevant people anymore. I plan to try to honor this commitment by having more respect for the experiences of children in general.

2: I didn't attend the expensive college. I did try quite hard to figure out if it was feasible, but unfortunately I was lacking in good information about money at that time in my life. My best guess was that it would have been pretty crappy graduating with that much debt, and I now think that was basically true. Ultimately, though, my life would have been so different that it's hard to say what the right decision was.

3: Haven't had the opportunity yet, but I do plan to have another child, even keeping in mind the agony of childbirth (note that I did have medical pain relief, but they don't tell you how bad it can be even with that). My past self wasn't aware of how great having a newborn child was, and I like to think would agree that this is the right choice all told. (Also, later births are on average easier, so that helps too.)

27!Austin apparently shares lots of values with 17!Austin, but I would submit not out of any moral principle. If 27!Austin has different values from 17!Austin then that's possibly sad in some weird sort of way, but statements like

if 27!Austin decides to ignore the values of 17!Austin, then that constitutes a kind of murder

are simply ridiculous hyperbole. If you literally believe this, then why are you not calling for anyone who changes their mind to be prosecuted and jailed for 20 years? Obviously not with the intent of rehabilitation, because inducing someone to change their values and beliefs is a kind of murder.

I take this a step further. I say that frontier14's opinion holds more sway than frontier!24's opinion. Frontier!14 has less information, but his mind is significantly more facile. Almost every single person drops iq points as they age. If in the intervening years I haven't gained any new information which refutes the reason underlying frontier!14's goals then I should on the whole trust his analysis over mine. Which is what I do.

This is more so an argument that it's rational to respect your past convictions, rather than that it's ethical to do so.

I think you'll find that this community will be very opposed to respecting the past because they are largely fans of hedonism. Honoring past obligations made to one self is kind of the polar opposite of hedonistic pleasure seeking behavior.

I owe the past my forgiveness, and the future my learning.

Adding religion to the equation immensely complicates this topic, since most religions posit the continued existence of the soul after death. In this case you're not really respecting the wishes of past people, per se, but merely people you can no longer see. When we talk about respecting the graves of the dead, I suspect it's a little of this persisting: maybe they're still there somewhere, watching. In this case, include their utility in relevant calculations, times the probability that they exist. 

The main topic that I feel is missing from this discussion is consent. There are always reasonable boundaries to what any contract, with yourself or others, can force someone to do, and we now accept that even legally-binding promises such as marriage can't bind our future selves unconditionally. Insofar as your future self is similar to your past self, your previous consent binds your future self, but even when contracts don't have official get-out clauses there are practical things that will prevent them from mattering. Although you're the same legal entity, I'd argue that in cases of Hollywood amnesia, for instance, the separation of past and future self is sufficient to make marriage vows morally dubious. It is only because of the similarity between 17! and 27!Austin that you can bind yourself to anything at all: I see no reason to generalise this obligation to your past self to your ancestors. They don't get utility out of your actions, so the only reason to worry about their opinions is where there is a contract you've consented to. You didn't consent to be created, so have no intrinsic obligations to your ancestors.
Regarding whether your descendants are forced to fulfil a will: they have not consented to the contract, but can simply not take the money if they wish. If they take the money, they are consenting to reasonable requests in the will, although if the requests are clearly absurd (such as saving something that has already been destroyed) then the conditions will just be ignored. 
"The people in the past were roughly as intellectually capable as you are": maybe in genetical potential, but not phenotypically, as shown in the Flynn effect. "The people in the past had similar modes of thought, similar hopes and dreams to you." They were mostly farmers with very limited capacity for abstract thought. To the extent that their hopes and dreams are similar to mine, I see no reason to double-count them. Furthermore, they don't have working knowledge of the current world, and giving them it would render them effectively different people, by your own arguments. 

So many things to ponder. I am this day 69!George. 19!George was a mess; 29!George not so much(quit drinking).  I miss the youth and energy of 19-65!George. Try as I might, the body and brain runs its natural course, but I am not complaining and try not to use aging as a mask for bitterness or an excuse for giving up on new ideas. I regard my ancestors with a mix of anger, sorrow, and joy.  I try to encourage hopeful thoughts about the future because I was lucky to have been able to live out an “average” life span, so I feel a responsibility to support conditions that would best allow future (and current lives) to live as simply and as well as I have been able to live. 

I disagree, because past people had their chance to influence us and I am equipped to influence my descendants. If I don't kick in for their values, or my descendants don't kick in for mine, it means the people in the past failed; they don't get extra control over me just because they hoped they would have it.

The closest thing I believe to this is that it's good to empathize with past people, and not dismiss the things they cared about as locally absurd. In my opinion, engaging with Catholicism at all is adaptive for a higher fraction of Westerners in the 1600s than now, leaving aside the fact that its epistemic claims are false.

It's also good to try to spend time with my aging relatives because I care about them, and because I want to model to my descendants how to care for me when I'm old, but again not for decision theoretic reasons that can be generalized from reasoning about future people.