I didn't even notice. The brain is cool like that.
Anyway, (iib) is certainly wrong, as you said -- the Big Bang happened everywhere in the Universe at once, and that's true whether or not it's infinite.
We don't technically know which, by the way. There's no measurement I know of that can prove the Universe is infinite, as opposed to simply bigger than we can ever see -- although of course that won't stop physicists from trying. (The Cosmic Microwave Background helps, a bit, to show that at least the Universe is larger than the Observable Universe, but that might be as far as we can go).
I think the Universe being finite is actually weirder. If it were finite then either you could travel in any direction and eventually hit a literal wall, or (more likely) you would do the sort of Asteroids thing, and eventually (in particular, in a finite time) arrive back at where you started. That happens if the Universe is similar to Earth, or to a doughnut, or something of that kind.
But a Universe that's finite, but also expanding, opens up the real possibility that it's expanding into something. It would have, in some dimension, a finite size, so that you could potentially imagine extending that dimension to beyond the bounds of our Universe and into... well, something. I don't know what. But it might have "room" for other Universes, also finite, and that opens up a whole can of worms and I don't want to go any further in that direction for now, as it's very speculative and anyway not really what the question is about.
So let's go with an infinite universe, and see if that makes more sense.
(TBC)