Yes. That's what I said.
No reason why not. If you had bothered to follow the links I gave you previously, you'd have found several hypotheses for multiverses.
No. We may be one 'universe' in a multiverse, or we may not - it's all speculation, as I and others have explained in previous posts.
If you mean a black-hole type of singularity, it would get shredded by tidal forces ('spaghettified') like anything else. Other than that, it's just a looped strip with a twist, it will just sit there until you mess with it.
How can the big bang singularity be 'more than one'? The question is oxymoronic. I can imagine an oscillating or cyclic universe, where a big bang is eventually followed by a 'big crunch' and a new big bang, in a repeated cycle. This has been proposed, but last I heard, physics suggests it wouldn't be sustainable in general, and our universe in particular appears to be heading for an ever-expanding heat-death, so there will be no big-crunch.
No, it's an event. Earlier in the post you used 'form' for the topology of Earth and the universe. A spacetime event is not a topological form.
You're back to nonsense/gibberish. An extension of what? Two spacetime events are just two spacetime events. You hit 'submit' there at 08:22 GMT, I facepalm here at 14:34 GMT. Where's the 'extension'?
Frankly it will be a waste of time. Finite has a perfectly adequate definition. If you want to define something else, by all means do so.
Really.. do tell.