I want to be sure about that one.

I understand the Invictus but I don't really understand the expansion part.

1. Basically you would get an expansion at launch with more maps, contents and vehicules?  
2. Does this mean the normal game have pay wall content?
   
3. Will it be possible to buy it in the future after purchasing the base game?
   

Normally with more expensive edition you get cosmetic or some gear but not that much content.