Yeah, as I said, it's only speculation on my part, but that's part of the fun...at least for me.
We don't have a lot to go on plot-wise yet. We know from Fusion that Adam was once her CO, and, from the trailers, as well as what we know from the demo, some of the other people in the team know Samus. "Remember me?"
From that, I'll assume that Samus probably has some sort of connection with at least some of the team members. Fairly late into the trailer, Samus clearly screams "Anthony", which is apparently the name of the "Remember me?" guy.
My guess just was that this was her old squadron, or at least some of the team members left were probably from her old squad. If that's true, then they're probably the closest thing to family that Samus has, albeit, in Samus' case, they are probably estranged friends or family. Since we know that the developers seem to be trying to humanize Samus with this game, and so much of the trailers so far have emphasized the loss of the "baby," I think it follows that much of the game is also going to focus on Samus' reaction to dealing with loss.
I'd agree with Deguello. There's not that many ways that this could go down. It doesn't have to be unpredictable and original to be entertaining, and I can't see a Metroid game being a comedy in the traditional sense. That's why I think the soldiers are probably going to be monster food.
The story might be executed well or it might flop; the trailer does still intrigue me, though.