This is exactly the plan. It took me 3 months of fulltime work to get those basics done right (and I already had experience with MMO networking before I started). Even the most innovative MMO concepts that I can think about still have registration/login, storage of persistent character data, chat, launcher/patcher and probably the same style of camera and zoom as in WoW.
I suppose it can be tweaked into a a different subgenre of MMO rather easily (since it is in blueprints). A MOBA is completely different though, you would have to write matchmaking, launch servers for each match, different camera, new AI for creeps, destructible structures, etc
It is completely open and almost everything is in blueprints. You would have to know some C# if you want to modify launcher and chat server since they are separate C# applications.
Not sure what you mean by this, but I do plan to add dungeon instances and server travel eventually, just canβt give an ETA right now.