I had the same issues prior to takedown--diversional pouchitis was what my surgeon referred to it as. Unfortunately for me I still have it and it is chronic 16 months later. That does not mean it will be the case for you. I do take daily augmentin to help with the pouchitis as without it, my pouch goes haywire.
I would ask your surgeon about his experience with this. Most will tell you it is very common to excrete mucus via your jpouch when you have a temporary ostomy
and then when your takedown is complete, it will correct itself once stool starts passing through the pouch.
I am bothered about you ilietis diagnosis as at my last scope prior to my colectomy, I was also diagnosed with ilietus (referred to as backwash colitis). My surgeon was not concerned about this, but now I am wondering if there is a correlation to chronic pouchitis due to this and maybe we are not the best candidates for jpouch surgery if we have a pre-surgery or pre-takedown ilietis diagnosis. Again, only your surgeon can best answer this question for you based upon his experience.
Good luck.