yes.
You can play first strike maps offline in both the split screen and XBOX Live -> Combat training lobbies. (Though for combat training, you'd still need to be online.)
No everything is free on split screen offline.
Both.
Yes, you can. You can play the campaign offline and against friends in split-screen mode.
The Annihilation map pack probably will work in split screen mode.
no
yes with in the 360 it has split-screen
Yes
yes
You can only play split screen on World at War if you are playing offline, and under the "Split-Screen" mode. This can be found in the co-op campaign, zombies, and multiplayer modes.
To play the Call of Duty co-op campaign in split-screen offline on PS4, first ensure you have two controllers connected and logged in to separate accounts. Launch the game and navigate to the campaign mode. Once in the campaign menu, look for the option to start co-op or split-screen; it may vary by game title. Follow the prompts to initiate the split-screen experience, allowing both players to enjoy the campaign together on the same console.
offline firefight coop surpports online 16 players, system link 16, and 4player split screen.