While I do not perceive Blalock's or Russ' performances as stellar I doubt that they were inspired by this Sheldon Cooperish pop cultural image of Trek fans and thus, as you pointed out, indirectly Vulcans. That would be pretty bad research by the actors and pretty bad directing which doesn't correct such errors.
I'd rather say that Blalock's T'Pol suffers from being often too wooden or too emotional, i.e. missing this sweet spot which Nimoy hit so often, this sweet spot of conveying ample of feelings between the lines via letting Spock pretend to be utterly distanced and rational while actually being ironic, sarcastic, arrogant, condescending or whatever.
I doubt that a Romulan invasion of Vulcan would be perceived as internal matter, the Vulcans are after all part of the Federation (think about your own fairly federal country, even die hard "more state power" Southerners who whine about DC and want less central power would never suggest that states should have their own military; if there is one thing you do together in a Federation it is defend your borders) and do not want to have to do anything with Romulus.
After all the main obscenity (from a Vulcan point of view) of Ambassador Spock's efforts towards peace is not so much doing this work in secret and on enemy territory but rather acknowledging via his acts that Romulus exists. At least this is how I read Balance of Terror. The Vulcans knew very well who the Romulans are but were embarrassed to reveal it after the war, they prefer to disavow the very existence of their distant brothers because they remind them of their past and who they could easily become. And I guess the empire wants to conquer Vulcan not because of military-strategic considerations but because they wanna annihilate this cultural mirror image of themselves. One culture pretends the other is not there whereas the other strives to eradicate the other. Cultural lunacy in the guise of cold logic, isn't this why we love these two Trek races?
There are other perspectives besides the psychoanalytical one. You could wear e.g. mythological-historical glasses and then the Vulcan-Romulan story would become the Greek-Roman one: Aeneas flees from Greece after the Trojan War, founds Rome and "later" (shift from mythology to history) the Romans come back and conquer Greece.
OK, this is just fooling around but it is kind of fun that there are such similarities.
About Vulcan pacifism, I don't perceive such a clear cut after the Vulcan Reformation. Sure, there are these lines in United
T'POL: Minister T'Pau is dispatching twenty three vessels.
ARCHER: That's all?
T'POL: The High Command has been disbanded. Many of our ships no longer have full crew compliments.
ARCHER: T'Pau could have picked a better time to clean house.
but I doubt that the war with the Romulans has been won without any serious Vulcan military engagement. After all the Federation emerges afterwards and you do not cooperate politically unless you have cooperated militarily and/or economically before.
I guess that the shift rather occurred after the foundation of the Federation, when Vulcan did not have to defend its territory on its own anymore, when defense became a common endeavour. There are probably relatively more Vulcan science officers than Andorian tactical officers in Starfleet.