Think nothing of it, I know what it's like to have a thread die because of lack of interest.
You're right on Scenario two, I had my Snakes mixed up there for a minute. Still, the forest offers a lot more stealth options for snake, and since he has access to the optic camo, I still see it going down in the same fashion. If I wanted to stretch it, I could claim that SS has genetic memory of the area, since he's all cloney of BB and stuff, but I won't go there.
That's assuming the mercs are going to be staying in the building in scenario three. I can understand them maybe wanting to fortify, but I think it's just as likely they'll be looking for some vehicles of their own to utilize. If SS is at the driveway, does that make him closer to any of them? Seems like whoever gets a set of wheels/tracks wins this round.
I think you might be underestimating Rex in scenario four. The big gun was obviously the rail nuke, but it still has access to a standard railgun, a pinpoint laser that can sweep across, and the radar dish will help Snake keep an eye on the air craft and just strafe them with rail.