A bio-oil is any form of automotive oil which is synthesized, as opposed to petroleum-based.
Probably scar tissue. Once its healed over, you can use mederma or BioOil to help make the scar tissue less noticeable.
You don't have to clean it anymore. Use an oil and massage it. You can use vitamin E oil, emu oil, BioOil, jojoba, or a similar oil.
Yes it is. To increase the chances, use BioOil, emu oil, Vitamin E oil, or jojoba oil to massage the ears and close the piercing. I wouldn't get them repierced until she is older because when babies get their ears pierced, they usually shift and become uneven because their bodies grow so much. Its a better idea to use stickers or clip-ons and she can get them pierced when she's ready :D
Depends how big your ears are stretched at dude, but if you take out your plugs/tunnels every night and rub vitamin e oil / biooil/ jojoba oil on it this allows the ear to relax and the blood to flow freely. They'l thicken up after a while of doing this. Another way to thicken them up is to downsize and restretch, downsize and restretch and so on. By doing this your allowing the molecules (i forget the scientific name of them =P) in your ear to heal and by downsizing and restretching you are eventually going to increase the number of said molecules eventually resulting in a thick ear. Its a long process but its better than having a snapped / torn stretched ear ! (: