I have the same OCD problems. A part of me wants the perfect starting crew, but I've learned to like that about this game. Now when I start a new game, I look through my starters and decide who's getting enslaved and sold ASAP. Usually I only end up keeping about a third.
I actually enslave every single one of my slavers at some point. Then I biomance them to Strong/Resilient. If they're male, I make sure they have an 8" cock, because it helps with Advanced Blowjob & Fellatrix training. I also grow a few to Monster size, because it's helpful to have 2-3 Juggernauts on hand, and I also make a few Btf or Exc for the same reason. Not too many Juggies or Exc's, though, because those traits have serious downsides for some missions. And when a slaver comes out of Dominance training, they also earn the Dominant trait -- Sub is real bad on some missions. (FYI, Switch seems to be broken. and gives the worse modifier, rather than the best.)
The best part of enslaving/retraining is that it sets the slavers level to Novice, which means that they level up faster, which means more perks on top of whatever they already earned.
At the endgame, every one of my slavers is Str/Res/Trn/Dom at minimum, and usually like 8 traits on top of that -- no joke. I make sure that anyone with negative traits like unruly, cowardly, etc. has been purged from the ranks by way of selling them to the Whore Makers. (Never get rid of slavers by sending them to die on missions -- it's a bad morale hit. Way better to watch them until they fuck up and get a bad rep, then enslave them, then sell them off.)