i have been working for a while on that topic and i collected from many of them infos they'd never have the courage on some cases to say on tv's and i am almost done with the writing of it ,it should be good for the weekend
for now i will give just an indication of how low they are considered,they are the only section of the whole musical setup to be called" mutu ya ",singers are called by their names and their roles,guitarists the same you have some who have a complete nickname,some who are x solo,x bass,x accompa,x synthé,you have drummers,you have mbonda players who have names but you will always hear the leader when he arrives at rehearsal or soundcheck and does not see mbonda players" mutu ya mbonda nanu aye te" while he calls all the rest by their names