Kid and Law are definitely going to face Imu
Imu's hinted to have immortality due to him having a name of one of the 20 kings. Meaning Law's probably going to have to do undo his immortality before Luffy beats him. However Law has never been good in 1v1s and has always needed support to land major attacks. This is especially going to be true for Imu, the strongest character in OP.
So chances are, Oda will have Kid be Law's sidekick like in the Big Mom fight. Kid will pin down Imu, Law will use that opportunity to undo his immortality. Both will get clapped in the end. And Luffy will save the day.