Hello.... I'm Canadian! We look forward to having you back.
I can't say much for health plans, as I work for the federal government, and Sun Life covers diabetes no question asked.
If you have to get private health care, I don't know what problems you may run into. There are other very nice canucks on here who may be able to answer that one...(beth, menace, kickstart?)
I do know that endo visits and the like are covered under public health care, as I never pay for those, just show my lovely picture ID for Ontario Health. so in that way you're covered, tho i'm not sure of the process of applying for your healt care once you arrive in whatever province you are going to.
I also know all my drugs and needles are covered by Sun Life, so I get 80% back, but i imagine each plan is a little different......
I hope i was at least a bit of help!