You've got a good plan Bonsai. Just be sure to list the vehicle on your B4 "goods to import" form when you land to avoid any taxes and duties.
Definitely take care of any recalls while you are still in the states. The recall letter you should request just before you plan to import. It's easy (it's getting any recall work done that's a pain), just call Honda USA and ask them to send you one.
I think paying off the car is also a good idea. I've heard some finance companies will allow the car to be exported, but it just seems easier if you own it outright, plus you won't have any more monthly payments! Just consider paying it off well before you plan to import so the finance company has time to process the paperwork, transfer the title to your name, and send it to you. You'll need the original and copies to export it.
Yes, the modifications can be done in the US, but you don't have to do them before importing. They must be done to pass Canadian inspections though and you have 2-3 months once the car is in Canada to get that done.
Don't stress about this stuff now. You've got time to get it all taken care of...just make a list. Do the US stuff now and keep the list for the Canadian part. All the best. Allison