Porting Skeletal Rig for Unreal Engine

I have made my own custom model for a game. However, the skeleton that I used for animation is not compatible with UE4’s 2Bone IK and other bone control features (because the skeletal rig is setup for animation not for realtime manipulation). How can I go about porting my skeleton along with all the animations that I’ve already made? Would I have to repaint weights? Re-animate? I’m using blender but if I accept Maya answers I’ll look into similar solutions thanks.

Picture shows incompatibilities highlighted in red.

Specifically, my leg bone hierarchy is screwed up and is parented in the wrong way that does not allow the foot to work with a 2 bone IK function.

Just dont export control bones to UE4. Export only those which deform the mesh. All their attributes get baked to .fbx