Somethings to look at before coating is applied:
ambient conditions
surface prep - profile, cleanliness
After coating:
visual of coating, looking for wrinkles, areas not with proper overlap, pockets, etc.
Holiday test - with high voltage holiday detector
Then you can make a decision whether you want to do a destructive test on the coating. In the case of a wrap, a peel test to test for adhesion.
As far as backfill if your product is cold applied, you usually can backfill immediately. If hot applied, there will be guidelines from the manufacuturer, you would wait until it is cured and cooled.