I would also like to know whether in the future it would be possible to replant hair follicles in the donor area (that was previously used for an FUE surgery), in order for hair to grow again in the donor area, in other words will it ever be possible for the donor area to grow hair again?

When hair is moved from one place to another, the area that was the donor area will have lost those hairs forever. They do not regrow and can not be stimulated to regrow. If you move them back (I don’t know why anyone would do this), then yes, they will regrow in the original donor area.