[gemy]

I just noticed that your 3.5 lb female went into heat, and you were asking basic questions about the heat.

If you have this 2.5 lb intact male in your home, you need to keep them separated, all the time she is in heat. Diapers etc, will NOT prevent a mating. Separate these two, exercise them separately, feed separately etc. Use crates, xpens, or separate rooms.
You do not want an unplanned pregnancy. She is way too young if this is her first heat.