Your plants are looking healthy and green! Although the pic you have put up don't illustrate what you are saying about orange/little white hairs. I could be blind. It sounds like shes on a good water/nute schedule, and has a sufficient amount of light, (as long as your growing in a cab. w/ mylar or flat white walls)

-In your concerns of her being a runt: How are the secondaries coming in? are they past 3/4 nodes from the stalk?

-I'm in the same boat with 2 short and bushies at 1month, with strong secondary production. (thats how i want them due to my space)

Flowering: If your plant has shown no signs of sex yet, patience. If you just put her into a 12/12 light cycle your going to wait about 1-2weeks before sex is shown. (white hairs for female/ little balls for male) got it, good.

Pot size: I wouldn't transplant after setting into the 12/12 cycle. Because your going to stress the plant out way to much. Before the 12/12 cycle i would say re-potting into bigger would help. Give her some more room to spread the love(roots).

Topping: I'm not a fan of it, especially if you unsure about the strain. Some plants have a harder time recovering from amputation like that. I would have suggested LSTing them (Low stress training) and that will give you a bushier plant without sacrificing limbs.