yes you can! i think the only difference is you get the map pack with game of the year edition rather than paying to downloading it off of marketplace. so the answer to your question is YES
Yes but Call of Duty Modern Warfare The Year Edition has a Key that, if used online, can give you the extra maps free from xbox live store or playstation network. So either no maps or free maps. It's also another way of making people spend an extra $10/£10.
No.
of course.
In my opinion, you should hold on to the other games if you can, but more people will be playing on the newer games online.
no
no it does not yes in campaign and when you play with people online
Millions, It's so easy to find a lobby
Yes you can play 2 people online on one console.
No you must both have the same game.
yes u can
No because they are both different formats
Not online but in regular multiplayer you can