1. You can, in fact, extract a baby. They will show up fine in bodyshop, have what are presumably the correct features when you age them up, and the only real issue is that you can't give them a hairstyle until you go into CAS. I'm very glad I found this, as I now know exactly what Gabrielle (daughter of Ben and Doc Nerd) actually looks like. I have to say, it could've been worse- some oddness, but she still manages to look pretty good, at least with the right lipstick to disguise the fact that she has an odd shadow under her mouth because her mouth and chin don't mix well.
2. Extracting a baby produces an unnerving missing-half-their-head effect when you age them up in bodyshop. It's unnerving enough that I'll probably reserve the use of this feature for very, very rare occasions.
3. I hate waiting for SimPE to load, then waiting for SimPE to close, then waiting for Bodyshop to load, then waiting for bodyshop to decide to be less mind-numbingly slow so I can get to the area where all the extracted sims are, then waiting for the various features to do the same so I can try to give them hair/outfits that don't make me cringe, then waiting for bodyshop to close, then waiting for the game (and all its various loading screens) to load. Waiting in general, in fact, drives me crazy. Which is why I'm posting this as I wait for the game to load.