Regarding your question #4 on health insurance, this is probably the kind of site you need to look at - BestQuote Travel Insurance and you can call them for faster assistance. You can get free super visa insurance quotes - seems like it's OK to estimate your dates now and then change to exact...
I've had experience with BestQuote which can give you a free quote comparing several options so you can see what's best.
bestquotetravelinsurance.ca/super-visa-insurance
I think you should search for insurance comparison sites as they deal with several policies. I've used bestquoteinsurance.ca in the past, they have a support line where you can ask them about your coverage options. Hope this helps!
This is probably the kind of site you should look at to research your options: bestquotetravelinsurance.ca/International-Experience-Canada-(IEC)-Insurance
Maybe you can call them for support as they can probably advise the right IEC / visitors insurance best suited to your situation... Hope...