Wakanda has okayish tech, but lacks magics and raw manpower compared to hegemonies of Khesht
If they start far from hegemonies, they're nice backwater civilisation until some of supercountries arrive
Protectorate is human-centered civilisation, so interaction would go okay if Wakanda will believe in humanity. Like, idea of humanity is a religion to this guys. If not, they'd bomb the shit out of wakanda.
Union is alliance of all the species who decide to join and obey laws. This guys can be obnoxious with taxes and "we get your tech and magic, you get part of ours, we decide which." If wakanda does not join, the scenery is unsettling: military spear of Union is Shaz Empire. Being one of Union founders, and having retardedly powerful military, shaz conserved their own laws and tradition. Because they are constatnly in conflict with something, Empire is ultimate warmachine. As greyskins are very fond of violence, and think "slavery is bad, but genocide is okay, we guess", they'd unmake Wakanda and it's citizens in less than three days.
Rainmeni Kingdoms would basically clusterfuck wakandians into thinking that rainmens are bros and alles, slowly draining wakandians of all their money, goods, culture, scientifical achievments and anything else worthy. And then make wakandians provoke Shaz Empire.