We'll be on a Canada cruise shortly and have been on a few previously. The best idea is to layer. I'm usually warm so onboard I'll probably be good with T Shirts, but will also take a light jacket or sweater. I can layer that under another jacket for going into port. Also, a waterproof jacket or poncho would be a good idea. And an extra pair of walking shoes, wet shoes are not fun.
If you're in the Haven, which it sounds like you are, the Concierge will have all the menu's for the specialty restaurants. I can't remember if they are also on the TV.
I don't think there is a "luggage assist" after the cruise, but maybe someone else knows for sure.
There are thermostats in the cabins, but since I like a fan and DH likes it warm I usually bring a battery operated fan with me. Never had any problem with humidity so can't help you there.
Hope you have a great cruise!