Hello,
1. HikaAuction will be a component like HikaMarket or HikaSerial.
2. For the moment, the customer will only be able to bid with money, and the winner of the bid will be able to select the payment method he wants to pay the final price of the product.
3. Sure it's possible to force bid increments, but for the moment we'll only have a unique bid increment for the entire auction (we already added that feature on our TODO list).
4. That won't be possible for the moment because no money/point is deducted from customers until we have a winner for the auction, and THEN the winner will be able to buy the auction product for the final price.