some queries

[FG28_Kodiak]

to 1:
The event
OnPlayerConnected(Player player)
is only called if a remote player connects.
If the player is already on server and the mission starts nothing happens. Only new player are registered.

You get the host with
GamePlay.gpPlayer(); //Player is single Player or Player hosted mission - Server if Dedicated server.
GamePlay.gpRemotePlayers(); // all remote connected players, without the host (Player or Server)

to 2:
Do you mean how to add a AAA to a custom convoy?
On the object dialog -> Actor -> change the category to tanks and select a AAA (SDK 10/5 with 2cm AAA for Example).

to 3:
dont know the problem