Blanchard is like Congolese people "nzoto muke" and he used to be one of Koffi's favorites before messing it up, so it will be much difficult to do that. Another is that Congolese musicians often fear about what could happen next, will they send gangsters or soldiers to my house, will I find a band to play or be accepted in another, will not travel Europe anymore, etc. Look how Babel got fired just because of saying to Emeneya that he didn't sung well. Imagine what could happen if you fought with your boss. Also fighting with your boss/parents/uncle/granddad is seen as massive disrespect in the Congolese culture. It has been said that if you dare to do that that you are cursed. For example, how people often used to claim that Bendoson was cursed, after he left with Ramazani and co, because of the rumors that he tried to beat Papa Wemba at the airport, while the rumors were not true and it incident being the other way around.
JF Ifonge's case is different. JF came from Europe and had connections with "Ba Zulu" and "New Jack" gangsters so he knew that if he does something to him, he will risk that those guy can kill him when being in Europe, burn his car or house, attack his relatives in Europe, etc. That's why he was fearing for him a bit. A good example, is when he asked his mother to immediatly take JF Ifonge from the airport when coming from Kinshasa. Because of hearing that those guys were reading to create havoc at Bercy (like many concerts that got interrupted in Paris and Brussels back in the past), since that JF Ifonge got arrested in Kinshasa and Koffi not really wanted to do anything about it.
About Jordan I don't really believe that he would confront Koffi physically, maybe with words but not with physically. Most musicians always fear their former boss, although making alot of noise on television. Look how calm Suzuki was talking to Koffi about Lebou's mourning and all other former ql-members being quite.