there are numerous suspension forks on the market, and most of them are available with mounts for cantilever and/or v-brakes (no, the brakes on your mtb are not "sidepulls"). It won't hurt you if the fork also has disc mounts, as long as it has mounts for cantilever and/or v-brakes.
I'm no mtb expert (my only off-road bike is a singlespeed with a suspension stem) but there should be tons of forks that fit what you're looking for.

And if you're just commuting, get a rigid fork. No need to spend $300 though, just get something that matches the geometry so doesn't throw off your handling.