We're given very little information, and that's probably a good thing as that essentially means Coogler can pretty much interpret things how he wants in regards to whether or not Wakanda as a whole just accepted what happened.
We know the Jabari tribe agreed with T'Challa. That could simply be short hand for saying Wakanda as a whole sided with their king. OR the absence of the other tribes could imply a lack of unity which Coogler could choose to play with, if he chooses. Basically the Russos left Coogler with plenty of room to interpret how Wakanda reacts to Infinity War anyway he wants to. M'Baku and the military directly under T'Challa's command standing by him is all we know, and for the purposes of an Avengers movies it's all we needed to know. Coogler can fill in any blanks he wants to fill it, or just move on from it entirely (though End Game may or may not change that).