Thigh, nape and beard hair to fill in gaps/scars from FUE?

Hi doctors. I previously had FUE done (500 double hair grafts taken) and it has left some gaps in my donor area. I know SMP is an option, but it’s not one I want. I cut my hair very short, and those gaps are very obvious when hair starts growing out. Now I know beard is a good option for scars because it grows long. But I don’t have enough beard hair. Would leg and nape hair be suitable since I’m only looking to the hair on the back and sides very short (0 or 1 guard) thanks.