What is the best way to insulate embedded joists in a basement Montreal Home?

Hey there. I've recently purschased a house in Montreal Canada. We get -20C in Winter and we can get +30C in Summer. 

I have a split level home built in 1961 that is pretty drafty. I would like to start with a basement remodel. The walls are currently made up of mineral wool insulation with studs on 16oc all the way until Joist levels. ( Not insulated) can touch concrete. And no Vapor barrier. The basement is also dry and not humid.

The joists are fully embedded inside the concrete slab. Hence, the floor above close to the baseboard is very cold. 

My plan is to fully demo the basement walls and start from scratch. 

I've been getting mixed opinions online about properly insulating the "rim joist". Some say it will rot if insulated. And if insulating the rim joist use only 1inch max. - Link Section 6.2.6 "https://www.nrcan.gc.ca/energy-efficiency/energy-efficiency-homes/make-your-home-more-energy-efficient/keeping-heat/keeping-heat-chapter-6-basement-insulation/15639#a6-2 "

I want to use a professional company to spray foam the joist area while using XPS ridgid boards for the wall and floor. ( Top of slab)

Whats the best approach. 

Thank you