Another Canadian here!! We just got back from the Feb 1 Western 7-day cruise. Some answers:
- no bugs of any kind were spotted
- sea sickness was never a problem for us (calm seas..)
- snorkelling is not a problem. My 7 year-old had never done it and is a weak swimmer. That said, we snorkelled in Grand cayman and
Castaway Cay for hours. Just wear a lifevest or (better yet) use the standard inflatable vest that they hand out at ALL snorkelling excursions.
- never been on the subs, my friends tell me the fully submersibles are the best bet (Atlanis is the name I think)
- excursions are always in sync with the docking times. Never fear. Your excursion will meet in one of the ships lounges first, where you'll get instructions, a guide to follow, etc.
- Immigration was never an issue. You'll surrender your passports at cruise check-in. You'll be precleared for all ports-of-call. You'll need your "Key to the World" card (given to you at registration time) and some piece of photo-id (driver's license is good) to get on and off the ship. Typically, the photo-id is needed to get back onto the dock when heading back to the ship. On the final day of the cruise - disembarkation day - you'll need to drag to your family in front of US Immigration. This happens at 6am in obne of the lounges. The night before you'll be given a customs form to fiull out and bring with you to Immigration. There you'll answer a few questions (i.e. where are you headed when you leave the ship...) and then will be handed your passports. It's a 2-minute process. One tip.... make photocopies of your passports and keep them with you 'just in case'.
I must add....we departed Florida this past Saturday and really expected big delays since the Security Colour was changed. We were pleasantly surprised how efficient and downright courteous everyone was!!!!! And our luggage - with al lthe extra searching and handling - actually made it back home with us!!!
Whew... my fingers are tired!!!