I don't know anything about the movement, so can't comment on the earlier points.
>If AGI has even a 1% chance of happening this century and those donations reduce the risk of it going wrong and killing everyone by 1% that's still money very well spent.
Ive seen this argument many times on many different issues and I think it's almost always bunk. The classic example in Fusion research, I had friends when I was a student in the 80s arguing that if we only doubled fusion research spending we'd have unlimited cheap electricity by the year 2000, or others said that AI was the most important thing we could be researching at that point.
The problem is if you're too early on in the development process of a technology, you just flat out don't know enough about it to be able to make informed decisions. That early phase is about exploring avenues of research and figuring out what works and what doesn't, and that takes an irreducible amount of human time, diligence and hard work. Yes you need to invest in that, but above a certain threshold anything more you invest is almost entirely going to be wasted.
With general, or strong AI we only just barely have the beginnings of an idea of how to even do preliminary research on it. We're groping around in the dark for a starting point. It's far, far too early to start worrying about controls and management strategies for the end point of that research. I think there's very little chance much of that is likely to turn out to be relevant, and there's nothing to stop us focusing on that area once we do know what is going to be relevant.
I'm not saying ignore the issue, or don't think about it at all, but the idea that it's some urgent issue that we absolutely have to invest heavily in right now IMHO doesn't stand.