I assume you have public sewer service? That makes it a bit easier.
what about parking offstreet for an additional tenant? That could be a problem.
Once you find that stuff out, let me know if you need additional help. I know a few good local RE attorneys that could make it easy, and they are reasonable. Thanks and good luck,
Contact a local attorney who is experienced in working with your local township in obtaining "use" and "zoning" variances.