On aces, you receive one card on each ace and you may NOT re-split or double down. On splits, you must match your original bet. You may split cards of equal value. You may double down after splitting. You may double down on any first 2 cards except blackjack.
All double downs receive one card.
You may wager any part of your original bet. Blackjack pays 3 to 2. Blackjack is an ace and a ten count card. It is only a blackjack on the original 2 cards dealt. Insurance pays 2 to 1.