Congratulations!
1 - They can land after their medical expiration, as long as their visa is still valid - so no need to worry about that.
2 - Yes, they can bring a list of items that they may want to bring to Canada in the future.
3 - As far as I know, they don't need to apply for their first PR card, that process begins automatically when they complete their landing. They will receive the cards in the mail.
For the SIN number they can apply online, or at a Service Canada. They will need either their signed COPR or PR card.