I don't know where in Canada you are, but if you are diving in the Pacific, you will definitely want the overlapping, Farmer John type of 7 mil suit. And yes, it is possible to breathe in such an outfit -- we routinely certify students in wetsuits! It does require quite a bit of weight, but honestly, our students don't need as much weight to sink as I do, in my dry suit and heavy undergarments. I do agree that, if you are going to dive wet in cold water, you really need your own suit, because a well-fitted wetsuit has much less water circulation through it, and is therefore quite a bit warmer.
I also agree that, if you are going to dive in cold water, having an environmentally sealed diaphragm regulator is probably a good choice. Freeflows happen! And although they are definitely surviveable, it's stressful and puts a rapid end to your dive, so avoiding them is the best course, especially if you are able to make your original regulator choice with this in mind.
As far as BCs go, you CAN buy a simple single tank BP/W setup and dive it quite well in cold and warm water. I used my original stainless plate and 30 lb wing for local and tropical diving for quite a while (and have gone back to it, since I am now diving dry everywhere). Although a five pound plate sounds like a lot of weight, if you put most traditional BCs on the scale, they will come close to that, and they don't come apart into pieces for packing
I also agree that, if you are going to dive in cold water, having an environmentally sealed diaphragm regulator is probably a good choice. Freeflows happen! And although they are definitely surviveable, it's stressful and puts a rapid end to your dive, so avoiding them is the best course, especially if you are able to make your original regulator choice with this in mind.
As far as BCs go, you CAN buy a simple single tank BP/W setup and dive it quite well in cold and warm water. I used my original stainless plate and 30 lb wing for local and tropical diving for quite a while (and have gone back to it, since I am now diving dry everywhere). Although a five pound plate sounds like a lot of weight, if you put most traditional BCs on the scale, they will come close to that, and they don't come apart into pieces for packing