No. Once someone pays for the ticket, the money is charged and you would need to make a manual refund. That’s how Commerce works.
Nope. Money goes to the raffles submitter but Commerce always Treat it as account credit. User will have to request withdraw to receive the money in their PayPal, etc. Again, that’s how Commerce works.
Yes, there’s no integration between them but it can be easily done in a future version.
No, only one ticket per giveaway; this is to guarantee everyone has same odds in giveaways. Only in raffles you can purchase more than one.