You will get a perfectly compliant rig for CMU and BVH retargeter works perfectly with it. mhx2 MakeHuman format and get the add-on for Blender for importing MakeHuman assets.

Do not use FBX from MakeHuman to Blender, use the.

If importing from MakeHuman, make sure to use the CMU skeleton.

If using MB-LAb, it has it's own bvh importer and they work well with ACCAD bvh - but not so well with CMU.

Do not use 'transform rot and scale' - ONLY transform scale, otherwise you will get messed up results. you often get errors 'rot & scale' when using bvh retargter.

You can then retarget mixamo rigs using 'bvh retargeter' to CMU - though not reliably.

dae (collada) and then exporting via obj or fbx and use mixamo for animations and for auto-rigging. The best way to get Daz characters into blender for animation is to bring them in via.

Daz 3D rigs also import via FBX unreliably.

Rigify and Blender rigs do not work with CMU (without fixing the problems you mention).

I have been wrestling with similar problems and I may start my own question, but in the spirit of cooperation and helping this is what I have found:

Blender mixamo rig