Well usually mucous in the stool is indicative of parasites too, but no those are definitely something. Some of those in the huge photos look to even be covered in biofilm, or in their larval stage to me.
Check those two out, they both seem to be encased in a mucous like biofilm/substance.
Only reason im using that website for photo comparison is I have passed a few of the same specimens, specifically this:
and this:
Cercaria:
MY PHOTO:
NOTE the slimy mucous it was encased in before i pulled it out with Q tip.