Oh he's a beauty! SO glad you were able to save him! It's terrible that your lab partners felt they should hurt/kill any living creature!
The 1 gallons should be fine for now. If you need something smaller, a 5 gallon to split will be just fine. For now, just make sure you keep the water around 78-80 degrees F. A small plant and hiding place for them would be great! Also, I would suggest putting something on top of the bowls because Bettas are jumpers! Good for you for keeping on top of the water changes! 1 gallons should have 100% water changes at least twice a week. I'm assuming you are using a water conditioner too. :D