On my current playthrough I chose the Yes Man route to have a greater freedom considering factions. I was a bit disappointed when I learned that I also have to do the NCR-questline to keep the Brotherhood of Steel intact. At the moment I've invested 50+ hours into this character and am lvl 26. The next quest for the NCR would be the Gomorrah one and it would deny me to enter the Fort [, because at this point it I would have done to many NCR-quest in Caesar's point of view].

My questions are:

1. Does it matter if I kill Mister House before I get the NCR-quest to do it?
2. When I activate the Securitron-Army before I install Yes Man to the Lucky 38 Mainframe would it still be Yes Man's/my army after I install him?

If it is possible I would like to first kill Mr. House, and then activate the Army. It would safe me from killing the whole Fort again. But if I do this am I still able to continue the NCR-questline up to the point where I can choose the destiny of the BoS?

P.S. Spoilers doesn't matter for me, because I've already completed FNV once.