1. The enemy transport that is in the sea zone that you have to use for the amphib landing MUST be killed before you can attempt the amphib.
2. The DST remains alive and can return fire.
3. Two hits to kill a BB, whether from SUBs, aircraft, or from another battleship
4. It is the ATTACKER’S CHOICE which units (if any) participate in which battle. With the AC and 2 FIGs, you can send the AC into the Naval Battle, or keep it held back. The FIGs can fight either at sea, in the land battle, or one for each. So you can split it up however you like, you just cannot use a unit for more than 1 battle in the same turn.