I've done few fasts as well, 10 days IMHO is in the limit and you can definitely get refeeding syndrome, but probably just light one. Of the few times I did 7+ days fasts, I only got it once, and that was when I ate a lot for breaking the fast. Which obviously I shouldn't have done in retrospective, and the only symptoms was moderate stomach pain for few hours IIRC.

I do agree that at 10 days (YMMV!) you probably don't need those crazy refeeding ramp-ups of broth and soups for 1-2 days then soft foods for another few days, etc, but also don't just stuff yourself until you cannot move! Since you can chose, take a couple of light/easy to digest meals before going back to normal.