No, but then they've never had a series as prominent or important as Uncharted either. I think it could go either way, although I do think asking for two concurrent original IPs from any developer is a big ask.
Right, but you can't say this is the game they are making immediately after TLOU, for all you know it could be another Uncharted, and then a new IP. Im sure Sony doesn't want to not put out Uncharted, especially against Halo. Its one of the most visible Sony franchises now.
I bet they're not working on it, but they're planning on working on it. This might be the project that the guys who just finished TLOU will work on after being done with the DLC for the game.