I think Innoss B fuses a bit of Swahili into some of his songs too.
Possibly because by now Cogolese music became Kinshasa dominated. Earlier there were artists in Lumumbashi singing in local languages (I guess it is Swahili), like Mwenda Jean Bosco. Apart from him I don't know anyone who sang in this language and was famous in Congo.
Unfortunately I don't know that Wenge MM song, I am not very educated about their songs. But it is rare indeed to find swahili songs released by top Congolese bands recently. I think earlier it was more common because Katanga was a very well developed territory. Many recordings from the fifties and sixties from Congo include artist from the copperbelt singing swahili and Zambian languages. I think back then it was not that obvious that Kinshasa is the centre of modern music. But who knows, I am just guessing. What I miss is that Katangan guitar style was unique, it is a pity it has somehow lost importance.
One Congolese atalaku here in Kenya contents that it is hard to get the "feel" using swahili as opposed to lingala. He says it is just not the same. Here is my best swahili/seben by a Tanzanian band even the atalaku here uses swahili through and through..I dont know if this band consist of Congolese or Tanzanians or a mix.
Katangan guitar style is Mwenda Jean Bosco and others, some of them appear on this CD:https://open.spotify.com/user/nichollsgg/playlist/7hk6aoSarKSGRw5W1HzwvLMy personal favourie is the Kachamba Brothers from Malawi who played a similar style: