Thanks very much for reading and taking the time to give this feedback. It's much appreciated. I'm taking it all into account and plan to do a more rigorous investigation with a deeper, more neutral look into the evidence (one problem is that when it comes to CCT, metta meditation etc., there aren't too many studies assessing their direct impact on altruistic action). But it seems obvious to me that they can do this, after I have experienced it very strongly in my own life, and have seen it happen in others, too - but all this has definitely given me some personal bias/motivation to argue for their dissemination!
This post was, I guess, a pretty rough initial outline of how these practices might help a lot of different causes.
You've certainly helped me be aware that my enthusiasm for these practices has overshadowed my commitment to solid evidence, and for that I'm grateful.