There are no major differences -- a BC is a BC. However, you will not be able to demonstrate disconnecting releases to remove equipment, or (unless you install weight pockets) will you have integrated weights to demonstrate. We have not found this to be any kind of big issue. Neither Peter nor I dives a backplate during the pool work, but some of the other DMs who assist us do. We both dive them in OW, where no demonstrations are required.
PADI does not care what kind of basic equipment you use, within very broad limits. As already stated, dive shops can be far more prescriptive about what they want their instructors to use.
As far as your question about becoming an instructor goes, here a story: When I got certified, I found that, to my surprise, I LOVED diving. I wanted to do as much of it as I could, and I immediately wanted to learn how to teach others. That was basically the pattern at my dive shop . . . folks got certified, marched through specialties and Rescue, and became divemasters (often in less than a year) and then instructors. I was headed right down the same road.
And then, on my 20th dive, I dove with NWGratefulDiver. I looked at someone in the water who had skills I didn't know existed, because I had never seen them. From Bob, I went on to dive with other people who were amazing in the water. I began to learn things like gas management and decompression theory that I hadn't known were even there to be learned. I realized that I was truly a tadpole in a big pond, and that I had no business teaching other people how to do this when I knew so little myself.
Five years, about 7 or 800 dives and a whole MESS of classes and dive trips later, I thought I honestly had something to offer, and went ahead and got my DM certification.
Not a judgment, just my story. I'd recommend looking around you and finding some of the most experienced and highly trained divers you can, and spending time with them. It's an eye-opener.