First off as an insulator of 10 years I must say you did a wonderful job. I know how anyoing it is to work with roxul, it's awful. Your batts are very nice clean cut, friction fitted to your studs.
What mil poly did you use ? 6ml ?
Your Polly job is nice as well, I like how you taped the windows and doors to on top of the acustical .
A thing you can keep in mind for next time is to do the caulk behind the Polly boots of your outlets, so to seal it because the tape drys and is known to separate after a period of time; It's code to do that In All houses in kamloops now.
Also you said your ceiling was like a wall did you make sure to put vents (baffles)in the ceiling all the way through on every run?
RE: Tiny House Episode 11: Installing the Vapor Barrier