I killed off Cesar and most of the Legion (although I always get 4 to 5 stragglers to run up and attack me the moment I fast travel).

I have to assume even though I killed their leader, the game simply replenishes them and thus the battle goes on as planned.

I kille off House, hoping that I would gain control of NV (if that's possible, I haven't found it yet) and I'm just wandering around sniping off legionares, trying to get head shots from as far away as possible. But that's getting out and I'm now heading into the sewer system, but I pretty much have covered all that as well.

The Legate Lanius and the rest of CL at the battle of Hoover Dam, along with the Fiends.

Who?
I'm holding out accepting the Point of No Return option (I want to keep playing for a bit before I end the game)

Joshua Graham's replacement. You'd almost think he doesn't exist...or really doesn't do anything...he could be the most over rated/hyped npc in the game.

"Hi Lanius, how are you?. Nice sword you have there."

He talks about some kind of jibberish

Then I reply with "say hello to my ji-normus machine gun"

Maybe, just to really go out there...maybe I should suit up in BOS (I have yet to find the Enclave armor) and play the insane card and start going after the NCR and everyone else in the game....LOL

To hell with my good karma level. I've got plenty of weapons and ammo and 15,000 odd caps....time to go rogue.