So glad i hit upon this thread.
I had a similiar use case as that of OP's. Didn't find Rp3 performant enough, so i have odroid c2 running librelec. But now i want to run retroarch with kodi on another microSd on C2. I did similiar permuations with the images but just like as OP's they all failed.
If anyone got it working on c2, it would be greatly appreciated if they can contribute in updating the wiki or let know even if they were able to do so, so that investing time might be worthwhile. The "retropie-4-x-on-odroid-c2" link is helpfull but can't fully grasp if some steps are obsolete or still required.
@Phil333 did you pursue this further or dropped it for now?
thanks for this thread tough!