Without going into long expositions that you can read elsewhere:
https://www.reddit.com/r/soma/comments/3...e_written/
https://www.reddit.com/r/soma/comments/3..._spoilers/
The short answers are:
1) Simon-2 (The Simon in the softsuit) is an AI construct, not a scan of a person, that WAU built from scratch based on the brainscan template of Simon from 2015 (Simon-Prime). We know this from a number of sources within the game, but I won't bore you with citation.
2) I am not sure what you are referring to. Simon-2 was always in a soft water suit, but the human conciousness has self-defense mechanisms to protect it from the stress of existential body horror. Simon-2 just originally hallucinated having human skin hands.
3) There is room for interpretation on this. However, we do know that both Simon-2's and Simon-3's physical bodies are nigh immortal and nearly indestructible. As far as the personalities, it is possible that:
A) the psychological stress outright killed his personality
B) The psychological stress caused him to black out for a few just like when a monster "gets you".
C) Catherine-2 shut him off on a time delay (unlikely)
D) Catherine-2 outright killed him and created the option for you only as a stress reliever (possible)
E) He will regain consciousness and go insane
F) He will regain consciousness and not go insane
Hope this helps. If you have any other questions I can help point out my interpretations or cite sources for you to form your own opinions.