Every character will for sure experience muscle growth. No way around that. What other things grow will vary from character to character so it is not constrained to just one fetish. As there will be tons of characters to come you will probably get to see tons incorporated.
Hyper is not on my radar, as I personally am not a fan of it but there might be in the future nevertheless.
Weight gain / fat gain is a for sure a no. I hate this fetish so I won't ever do it. There will be some characters that are fat but not anything too extreme.