To my understanding, it was removed because it corrupts the game.
They can currently join existing kingdoms (like successful rebel clans).
That would be discussed once it is reasonably certain (read - not definitely confirmed) what will come and in what general form. Aka "Improvements to X" would not make for a particularly interesting read - so some level of detail should be provided.
Platform version increments are based on releases (actually, even certification submissions in some cases IIRC). That's why they differ between PC, PS and XB. 1.15 or 001.015.000 should be correct for PS4 and PS5.
Yes and given the reports regarding battle stability and AI "over-performance" that's the right choice to me.
No, there are general combat AI score calculation changes. Tournament participants in later rounds just receive an additional bonus to their score.
Different branches are worked on concurrently. x.x.X patches focus on critical bug fixes and minor balance / content changes (in beta, live usually won't see content changes). x.X.x patches introduce the regular feature & content changes.