Collector plates do indeed differ from antique. I can guarantee that antique plates do exist as I use them for some of my vehicles that are used only for parade or display. They also allow trips to the repair shop.
Here is a cut and paste from the autopac site:
https://www.mpi.mb.ca/en/Reg-and-Ins/Registration/VSI/Pages/reg-safetyandinspection.aspx
Vehicles excluded from periodic mandatory vehicle inspection requirements include:
... motor vehicles registered as the antique vehicles registration category
...............................................................................................................................
As to the out of province requirement to provide a certificate of inspection, if it is an antique, it is covered here:
https://www.mpi.mb.ca/en/Reg-and-Ins/Registration/VSI/Pages/coi.aspx
Certain transfers of ownership are exempt from the COI requirements. These are:
....Any transfer involving a vehicle to be registered as an antique motor vehicle.