In regards to tests performed for possible ileostomy reversal, what does this mean: scan to check that timing for reversal is correct?

Depends: Each individual surgeon has their own protocol. I suspect a Barium enema to clear the colon.

Anastomosis intact: Purpose of an ileostomy is to allow function of small bowel when there is a colonic problem. If total colectomy, then an end ileostomy is performed If ileostomy is used to protect a distal colon resection where continuity is provided by a an anastomosis that may have compromised circulation the ileostomy protects the anastomosis. until healing demonstrated by x-ray studies.