Yes, you should call a vote expecting it to pass. Releases can't be vetoed, so
it should be pretty serious objections to stop at that point.

For the mechanism beyond that, it can go either way - communities I've been involved in generally reach some consensus by testing RC labeled bundles before voting on the final release. I find this helpful because otherwise you get votes mixed in with issues and it can be hard to ascertain what the result really is.

I believe some others will vote earlier, and roll a new version number if the vote fails. These are typically mature projects that tend to have their votes succeed in most cases.

I would avoid rolling 4.0.0 multiple times, as that is likely to cause confusion about which is the real one.

Worth bearing in mind for the future too, you can certainly release something and label it alpha/beta/milestone and then release the GA later. Releases of source code don't attribute any particular meaning to its level of maturity, QA or marketability other than how you choose to label it.