Male testicles are tucked up inside most of the time so it's hard to tell just by looking. Due to the risks (not only with the anesthesia, complications during and after surgery are not uncommon) and cost, spaying and neutering is not common, so I would guess he is not neutered. It's hard enough finding a vet that even sees chins, let alone one that knows how to and has spayed or neutered one.
Also if you get a second chin you need a second cage. You'll need to quarantine the new chin in a separate room for 30 days to make sure it settles in properly, give you a chance to start establishing a bond, and make sure it's not sick with anything that it could pass on to your current chin.
You are right, not all chins will successfully bond, in which case you would need to house them in separate cages forever. Personalities seem to matter more then age, so depending on your chin's personality try to find one that matches. If Milo is dominate you want to find a more submissive chin, if Milo is submissive though you can try another submissive chin or a more dominate chin. Two dominate chins will likely not get along though since they will be fighting over who is boss. Even then there is no guarantee, it's like putting two humans together, not all humans like all other humans. Also even bonded pairs can sometimes have a falling out, just like human relationships sometimes fail, and they no longer want to be friends. So you will always need either the ablity to split the cage or have a second cage on hand, just in case.
I no longer have any suggestions for breeders in Alberta area, it seems most have stopped breeding around here. Maybe try the SPCA and Humane Society? Even if they don't have any right now you can let them know you are looking so they can give you a call if and when they do get any in. I also frequently see chins and chin stuff for sale around Alberta on kijiji.