15 cards left to go in the deck, 7 of which will be aircraft. As mentioned, I'll then split the deck into non-air (90) and air (36) cards, essentially, two separate decks.
Not as yet. What installations did you have in mind?
Some people have tossed in the idea of Floating Drydocks and looking them up on U.S. Naval History and Command. They are based on the Friendly side of the map and if you have damaged or crippled ships you can retreat or retire them and have them remove 'x' amount damage over course of one turn or once per game.
Supply depots could boost the points on General or Vital Cargo special ability, re-roll attacks.
The Land Airbase in-game (Not the Forward Airstrip) just holds aircraft. I saw someone make a card on Facebook where these two or four engine aircraft could fly out every turn instead rearming, add expert abilities to roll extra dice when making torpedoes or bomb attacks. Or give them the ability to re-roll attacks
Dockyards could could be used to negate Incomplete, Inactivity or similar special abilities that way your ship can get in the fight sooner. They could repair ships also.
These are just coming to my mind at the moment. Feel free to refine or just sink these ideas.
Erwin Rommel - "Give me American supply lines, British planes, German officers and Canadian troops, and I can take over the world".