How to assign a skeleton with missing bones?

That is it. But I dont want to switch to the adam anim BP. I want to use all of my animation data and my anim BP. Im trying to put the mesh on to my skeleton. When I try to assign it to my skeleton, with the exception of the head, the bones are labeled with the word “missing” and written in red. If I continue it says all animation data will be compromised. That is why ive tried to retarget the skeleton to the humanoid rig and so forth. I can swap animations between the two, but not the mesh. Thanks again!