Of course, MDR's gestures and facial expressions are almost worthy of being classified as nATyam! (OK, I exaggerate.)
Yes, very much so.. The dictionary meaning of abhinaya is "indication of a passion or purpose or expression of sentiment by look and gesture" and MDR fits that bill!! He can not help get into the character and so bhAvam in his music is natural.
What I am realizing over time is this: For MDR, gamaka is not (just) a musical attribute but a tool for expression of the sentiment, thala avartha is not (just) a rhythmical attribute but a tool for appropriately proportioning the sentiment and emotion in meaningful chunks etc. Similarly for other melodic and laya attributes.. In his music, they are all deployed for a purpose beyond just music.
If he can exhibit/cast other's compositions in such terms, his own compositions should be even more reflective of those things. Glimpses of that can be seen in the compositions you have referenced above.