Looking for a couple things as I'm trying to avoid obscene shipping charges ($40+). I'm in the Toronto area

If you can find things locally, you can save on shipping - good luck! $40 CAD isn't very outrageous shipping cost IMO since the postage rates have really gone up a lot in the past few years - both in Canada and the US. I only get upset when the seller is tacking on a large surcharge on top of the postage cost. (Needless to say, I won't let US shippers use UPS/FedEx).
In a big city like the GTA (Greater Toronto Area) you may have more options than I have in Victoria.

10" Round Hatch, Sealect or Kajak Sport... would probably settle for 8"

You could try phoning MEC, since they sell the KS hatch covers and might be willing to special order the rim as well.
BTW, if you can fit a 10" hatch, use it - there's a big difference in what you can stuff through a 10-incher vs 8". (I used an 8" front hatch on my first Mariner rebuilds...). The Sea-Lect Performance hatches are quite a bit better IMO than the KS ones.

If you get can't find a local supplier, I recommend Duckworks in Pt Townsend. Quick service and fair shipping charges.

BTW, if you do find a Canadian supplier for the hatches, there's a good chance that they will have brought them in from the US, and businesses need to pay brokerage charges and duties - which individuals can usually avoid. So it pays to compare the prices carefully.

Red carbon-kevlar hybrid fabric.

Good luck! :-)
You can find carbon-kevlar at ebay.ca - some suspiciously 'cheap' and others not cheap at all.....