Hi Figgy, I don't know about that trial, but I was on a trial and the good thing about them is that they keep a good eye on you and you generally get more check ups. I haven't heard of avistat - but it sounds interesting - it's great they are trying new things all the time - treatment is progressing so fast, even since I was DX 
I lost a lot of weight on chemo , but have put on weight since (almost 2 stone) and my onc. attributes some of that to steroids and some to a thyroid problem (and some to greed
). I did find the steroids made my face look very round, so changed my appearance a little (but it soon went back to normal) and also they affected my mood - made me a bit more irritable than usual. 
I think its common to struggle a bit with weight afterwards - for a variety of reasons, but not everyone does 
My hair came back reasonably quickly after chemo finished, but it came back almost white initially, then grey and is darker now. It used to be long and curly, and is now short and straight. (Friends with straight hair have had theirs come back curly). So I think there's a fair amount of variation in hair recovery and change.
I used baby body wash on my scalp and all over - you want something very gentle as skin can get rather sensitive.