Russia and Ukraine

[Deesse23]

Look at the linguistic and ethnographic map of Ukraine.

Ok

Much of Ukraine near the mouth of the Dniper is primarily Russian speaking and ethnically Russian.

Yes, and no.

About 3/4 of Ukraine to the east of Dniper is also heavily (about half) Russian speaking and ethnically Russia.

No
Lots of russian speakers, but mostly ukrainian ethnicity. Ok, ill grant you 50/50 in face of the fact that of your first three claims one is definitely wrong and one borderline.

 But most Ukraine to the west of Dniper is primarily Ukrainian speaking

Yes, as well as north of the Dniepr (rerd parts)

, with parts of Ukraine, primarily the parts stalin took from other countries at the end of WWII and appended to Ukraine, being primarily Romanian, Hungarian, modovians, polish.

Yes, minor areas

It looks very much like Putin meant to secure the northern and southern ends of Dniper river in Ukraine.

Where all those russian speaking (particularly in the north), ethnic Ukrainians are? Yes

Whether he will annex the eastern Ukraine to Russia out right is hard to say.  But I suspect that is the long term objective if not the next thing on the road map. 

Yes i would suspect that someone throwing out random threats of (global) nuclear war, wants more than just getting rid of drug addict nazi puppets of "the west", but rather has something bigger in mind
Ymmv

But he will undoutedly insist that the Russia or the eastern Russia dominated part of Ukraine

Those parts with all those russian speaking Ukrainians and this area in the east, where there is a "significant ethnic russian population"?

retain full control of the Dniper reservoirs, because controlling those reservoirs undoubtedly controls the agriculture of much of Ukraine. So Russian control of try Dniper river and its reservoirs ensures, from Russian perspective, permanent good,

From everybody elses perspective its a naked land grab. Ymmv
I noticed you still havent answered if we may grab: Silesia, Eastern Prussia, Memelland, Pomerania, etc...and of course Danzig above all.

Russian friendly future behavior of the part of Ukraine that is not under Russian control.

That has not been invaded in breach of international law? Yes, sure