Yes. Russian military doctrine is also pretty clear in that threats to territorial integrity of Russian federation are grounds for using nuclear weapons. It is basically the implied threat in the referendums announced for this weekend.

Dunno why that would change things since Ukraine has already made counter-strikes into actual Russian territory (Belgorod). But then again, Putin lives in make-believe land and the target for these outbursts is probably the population of Russia, not the west.

yes. That seems the obvious play.

Russia will then lean on other "friendly" countries to recognise the annexation(s).

Unfortunately, any unbiased observer will note that the sequencing is "odd".

I will note that it's hard to ascertain what the actual desire of the population in the affected regions is. If the population truly does want to align with Russia then democratically, they should be allowed to make such determination.

The manner in which this is being done does not suggest the Russia narrative is truthful unfortunately. Digging into the diplomatic dialogues leading up to the conflict(s) may shed light on motives / who is driving the agenda (is it really driven from the regions or is this a Putin initiated proxy war with the west).