What is wrong with Mixamo thumb rotation and how to fix?

Can someone please tell me what is wrong with the Mixamo anim thumb rotation, and how to fix in Blender?

I am using Auto Rig Pro in Blender 3, to retarget Mixamo animations (which I downloaded using their Bot character mesh for reference).

#1 First I downloaded their Bot character in Tpose. And lined up the Mixamo armature underneth my Armature (also in Tpose, but my thumbs are rotated different). 

So I rotated my thumb bone angles to match Mixamo thumbs. (After this pic, I also twisted my Thumb bones in Edit mode, so all twist the same - while still being at the same angle of Mixamo bones in Y and Z view.)

#2 (The only question is what do I do for the Thumb Twist in Edit mode - do my twists need to be the same as Mixamo twists for retargets to work? If yes, then what is the exact degrees that Mixamo twists its Thumb1 vs Thumb 2 and 3?)

#3 (And in Blender > Edit mode, do I need to Control + A = Apply the new Thumb rotations of my arma before doing retargeting? Or does exiting Edit mode, lock in the Rots?)

#4 Doing these steps are not enough > when I import a Mixamo animation (not in Tpose) and retarget - my Thumb3 (tip) is rotated (not twisted) wrong:

#5 (vs #6) Looking at the Mixamo arma, I see the visual problem: When I put the Mixamo animation in Rest pose – the thumbs are rotated straight and no twist.

#6 But when in Pose mode, the Mixamo Thumb2 and 3 are twisted differently than Thumb1.

(This has ruined my workflow for 4 months because I keep having to re-key animations after I retarget. I'd rather change the Mixamo thumb-rotation keyframe. But I dont know how.)

#7 So why is Mixamo's Thumb rots/twists different in Rest vs Pose mode????

#8 And How do I normalize the thumb rots? Do I do it in Pose mode or Edit mode?

(If I click the Mixamo armature > go to Edit mode > it jumps to the Rest pose where the thumbs are already straight. Thus I cannot untwist the Pose rotations.)

#9 [On the Mixamo animation Armature] - Do I need to Control + A = Apply Rotations of bones before retarget, for the twists to neutralize? If yes, when/where do I do this, in Edit or Pose mode? And with the armature in REST or Pose?

Please help, thank you.