Which ever one you enjoy the most first. Meta will change multiple times.
If you need to round it down more, try to avoid the ones that are way too specialized/map dependent, like mortis or piper, and more balanced ones.>>183815
Nita is a good enough choice. She's an infighter, but not super committed like bull or primo.
And it's pick ONE to max out, then get others to 9. You want at least one at 9 at all times after the first one.>>183843
Loosen up the purse strings a bit. Get a brawler or to up to level 9, 5000 is more than enough cushion if you're feeling indecisive.
Buy pp on your favorite brawler to accelerate this if needed.