Nice kilt - but I suspect that your little problem with the fell is due to insufficient width and if you sew it down at the same measurement it might pull out again, or if it holds, cause slight damage at the end of each pleat.

If you look critically at the photos there is a slight but distinct expansion at the lower edge of the fell. A little more width there and it will smooth out.

I suspect that you did not add enough ease to the actual body measurement, but if that is the first attempt I can't wait to see subsequent projects, you do seem to have quite a talent.