Question's from some who's returning. Hello there I'm coming back to play this game with a new account sense I can't remember the info for the original one that I use 3 years ago. Now I have some question right now so here it goes

I'm thinking of using a saurian for my science federation character, 
is this a good choice or is there a better race in the fed faction for science?

Should I go tac with all three factions or should have I one carrier per faction? what I mean:
1. Fed, kdf, rom tac for all three on first play through of each faction
Or
2. Fed is sci, kdf is tac or eng and rom is eng or tac

Does it really matter what race I use for a specific carrier?