the only thing wrong with takeda is the low kunai, make em mid, otherwise he's fine across all 3 variations and doesnt really need to be hit with anything else. (yes f122+4 is fine, giving it holes would make the string pretty useless, theres a reason they removed those)
make sonya's grenades go away on hit.
not sure what they should do to alien, they gotta be careful on this one.
mileena only needs a few minor changes to things like making teleport sai a bit easier to punish, maybe reducing the block frames of f1 a bit. She's pretty fair compared to some of the other characters.
as for buffs, im not even gonna go into who all needs them, theres a lot of stuff certain characters could be using.