Reveg to use as mother plant 2weeks into flower?

I flipped my plants (all from seed) 2 weeks ago, I was wondering if I can take one out and put back into veg to use as a mother plant? The white hairs have already started forming

Why not just take a cut instead?

You get wild growth from a flowering clone

As above I'd take a clone from it.
The answer to your op is yes you could take it from 12-12 back to vegging, you'll get some funky growth for a few weeks before it reverts back to normal veg growth.

Cloned at 4-5 weeks 12-12.

You'd be best flowering them, chosing the one you like best and cropping it saving some growth on the lowers and revegging. Since you don't know how each seed will behave until after you've seen it.

Obviously that doesn't give you a mother for a while.

Or you could take lowers off as clones now, reveg and flower when you want. Or keep the one you like the most.