on the original question - the bigs. i agree that starting kowalewski is objectively a little insane, if you are trying to win games (if you are playing young players for player development - that is totally legit, but then i assume you wouldn't be asking the question).
that said. i don't like your new starting lineup either. blake is a killer scorer, you want him doing as much as possible. ledoux is a quality scoring guard, and i think crouse can contribute a good bit offensively too. you aren't using him much but i think he can be a pretty quality mid level scorer. if you use him a bit more, with those 3, you have a good amount of offense. 1 scoring big is all you can really utilize. having both scoring bigs start feels like a waste. when you look at your backup line and the scoring there, i think it becomes a bit of a no brainer. you need more offense there, and have too much on the starting line. kind of an easy decision IMO. i do think calahan and langford will be able to do more for you by season end... i wouldn't be scared of using either of them a bit more.
i would start brazil with one of the other 2. honestly you should be starting him all regular season for growth purposes regardless. push his conditioning hard, thats the only real argument against starting him, his stamina. you can make your 3rd big your 2nd pf and 2nd c, over your 4th big, the crappy one. it makes very, very little difference in press, but it can't hurt, and maybe it will make you feel a tad better about benching one of them :)