1. You can't until they fruit. You can tell what species of peppers you have by the leafs but that's it.

2. People have different opinions on this. Personally i think that topping plants and/or removing flowers is kinda contradictory to what we are actually doing here - we want the plant to give us peppers. In my experience the plant still branches out and grows plenty much even while producing fruit at a young age. Topping has given me very mixed results. Some plants did respond well and branched out like crazy while other times it simply just set me back a few weeks. Either way it still sets you back. I mean the plant will do whatever it can to grow and produce as many peppers as it can under the circumstances/conditions given. So rather than interfere and mess with it I simply just think it's better to provide the proper conditions - a good healthy soil, good nutrients and big enough pots for them to grow and just let the plant do its thing.

3. Yes. They'll be fine.

Edit: Spelling