Well you joined May 3rd, 2010, which is when I would've had that avatar. I got the second one July 18th, 2011. Not sure when exactly I got the first, but it was before that time. I got the second May 23rd of last year. I may do change #4 strictly to switch it to something that works on forum messages, though.
Yup. I've actually only ever had three! This one, that one, and another one where this kid is walking down the hall and someone jumps in and RKOs him out of nowhere before that was even a meme. Need to somehow recover that since it owned.
If I had to guess, Xenforo insists that avatars not be below a certain size. When it saw yours it went "okay let's make this bigger" and so it did. But in the process it turned it into a JPG and thus it's not animated anymore. Try having'em make it again, putting it in a 96x96 area.
Just upload an animated picture! That's all there is to it. Though that said, ever since Xenforo happened, it's been screwed up. My avatar isn't always animated. Namely, when posting messages. I believe I read the magic dimensions to make it work everywhere are 96x96?