The recent, seeming requirement of online play has me curious so I'm pretty sure I'm going to cave and check (I don't use Internet on my PS4).
I would be floored if you *had* to play online in any way, although if it's a cool enough feature I'd pay the monthly whatever if it's worth it. Either way, alternatively, you could wait to see that without actually looking at the footage lol. it's not like this is co-op.
Kojima San himself asked fans to go in as blind as possible, so I skipped the above and I'm skipping everything else until November.
If you already know you're buying the game, I would recommend doing the same.
I watched the briefing trailer and while it certainly helps one make sense of what to expect in the game it's very very far from something spoilery that will ruin the experience. Seems like something that will happen incredibly early on and kinda of just made me go, 'ah.' instead of 'holy shhhhhiiiiiii!!' it's basically just characters explaining the very surface synopsis of the plot, and why Sam has to go do what he does.