Yes there are some "addons" that we will upload soon for admin panel that lets you add resources, researches, dark matter, buildings and ships... some releases from this forum already have them
Yes it is possible , if you check database every member has a language column (correct me if I am wrong) , I havent tested but if you make an inagem script so that when the player clicks , lets say, frech flag, it will modify the databse and , we already believe you have the french language folder, it will change the language.
Thats in THEORY
EDIT:
PS My 444 Post :X