Your analysis of China's 'invasion' of Vietnam in '79 leaves much to be desired. Suffice it to say (here) that territorial expansion wasn't the motivating factor, though pre-emptively striking Vietnam's military capability may have been. Earlier ding-dongs with Vietnam pre-date modern China and are thus.... entertaining but totally irrelevant. 1407!
The Spratleys are claimed by everyone, China's claims are no louder than those of the other nations concerned. Also it's about mineral resources, not territorial expansion.
Tibet was independant from 1911 to when? I make that 39 years. Are we surprised that China sees Tibet as being legitimately theirs? China did not, incidentally 'attack into' North Korea, to which it was allied in that conflict, its forces attacked into the south, but again, Chinese expansion was not the aim or purpose.
Taiwan, incidentally, doesn't even see itself as being independant, and many Taiwanese want re-unification, once the pesky mainlanders have got rid of Communism.
So I say again. Where's the evidence of Red Chinese expansionism?
You say, incidentally, that "Given motive, opportunity and means all countries have expansionist tendencies."
Don't see the USA as being 'expansionist'. Wanting economic and cultural dominance, yes, sure, but grabbing for territory? Come off it!