Look no further than Point North. aka Pro Fabrics. I bought olive, black and tan from them, and they are good materials, a tiny bit stiffer than I would like for my domestic machine, but a LOT easier than some other material I have encountered.
https://www.profabrics.co.uk/collections/nylon-webbing-outdoor-camping
I stitch mine with regular domestic machine (albeit an old one with metal parts) and with regular Guttermans SewAll. It helps if the machine is designed for sewing inside sleeves, with clearance under the body, but mine isn't, so modification of existing packs takes a lot of fiddling and bunching up of fabric. I have tried the thicker thread, using a 100 needle, but my machine can't pull the thread tight enough and I get horrible tangles on the back side. Straight stitch through two or three layers of 1000D is no problem, but throw some webbing in there and/or ask it to do wide zig-zag for a bartack, and it isn't happy. Thin thread and 70/80 needle and I get a tight, dense, zigzag bartack.
Are you near to any shops which sell farm supplies and horse tack in particular?
I can name 3 not too far away from me.
And, useless to look for strapping, needles, thread, rivets, stitchers, etc anywhere else.
I think it is useless looking for those things where you suggest, in the UK. If you are near such a store in the UK (which is not a given), and IF they carry webbing, and IF it is the right colour, it will not be the right weight and thickness. Actually, I have never seen any of the things you mention, other than strapping, maybe, in any farm shop in the UK. I am very fond of such shops and have visited four or five spread from mid Wales to Bedfordshire and Leicestershire. Low odds of success I think, could waste a lot of time looking. Thing is, you don't want just any webbing for MOLLE, the material, weave and thickness are important. Many webbing sold in hardware type stores is polyester, and quite a thick, coarse weave, which is a pig to stitch and tends to be too stiff for packs. Clearly conditions in Canada (or elsewhere) will be different, but that has been my experience in the UK.