Short version: What primes are good walk-around lenses for an indoor, dark, crowded environment where you'll be taking pictures of individuals or small groups ad-hoc, walking around and stopping in unpredictable lighting scenarios? This is on a full-frame camera and a flash (430 ex ii) is available. Will 35 and 50 cut it? Or do people use portrait lenses, 85 in particular, for such a thing?
As a quick background, I've had a 450D for a while, and a 6D (full frame) is in the mail and on its way. My lens collection is at the moment: a (Canon) 35 1.4L, 50 1.8, and a 70-200 IS F4L. I've personally taken some of my best pictures of people with the 50, on the cropped camera, making it effectively 80. The downside is that things felt VERY cramped, and you're always needing to step back a lot (not always possible in narrow areas, which is the topic of this question).
Now I'll be using full-frame, making my 35 35 and my 50 50. Does the 35 risk making a poor fit for this scenario, giving people big noses, making me have to crop a lot on the PC, making me have to get very close to people? Is the 50 the right match? Something else?
I'm taking pictures of people, so these are almost like ad-hoc portraits (with more than one person occasionally) without the ability to set up.