I'm not even 90% sure of that, but I am entirely certain that the LNC is true: suppose I were to come across evidence to the effect that the LNC is false. But in the case where the LNC is false, the evidence against it is also evidence for it. In fact, if the LNC is false, the LNC is provable, since anything is provable from a contradiction. So if its true, it's true, and if it's false, it's true. So it's true. This isn't entirely uncontroversial, there is Graham Priest after all.

You say you're not positive that you know how logic works, and then you go on to make an argument using logic for how you're certain about one specific logical proposition. If you're just confused and wrong, full stop, about how logic works then you can't be sure of any specific piece of logic; you may just have an incomplete or outright flawed understanding. It's unlikely, but not certain.

Also, you seem unduly concerned with pointing out that your arguments are not new. It's not anti-productive, but neither is it particularly productive. Don't take this as a criticism or argument, more of an observation that you might find relevant (or not).

The Categorical Imperative, in particular, is nonsense, in at least 2 ways. First, I don't follow it, and have no incentive to do so. It basically says "always cooperate on the prisoner's dilemma," which is a terrible strategy (I want to cooperate iff my opponent will cooperate iff I cooperate). It's hardly universally compelling since it carries neither a carrot nor a stick which could entice me to follow it. Second, an arbitrary agent need not care what other minds do. I could, easily, prefer that a) I maximize paperclips but b) all other agents maximize magnets. These are not instrumental goals; my real and salient terminal preferences are over the algorithms implemented not the outcomes (in this case). I should break the CI since what I want to do and what I want others to do are different.

Also, should statements are always descriptive, never prescriptive (as a consequence of what "should" means). You can't propose a useful argument of the sort that says I should do x as a prescription. Rather you have to say that my preferences imply that I would prefer to do x. Should is a description of preferences. What would it even mean to say that I should do x, but that it wouldn't make me happier or fulfill any other of my preferences, and I in fact will not do it? The word becomes entirely useless except as an invective.

I don't really want to go into extreme detail on the issues with Kantian erhics; I'm relatively familiar with it after a friend of mine wrote a high school thesis on Kant, but it's full of elementary mistakes. If you still think it's got legs to stand I recommend reading some more of the sequences. Note that human morality is written nowhere except in our brains. I'm tapping out, I think.