I would worry about zoning. Not too many towns allow businesses like this in a garage, and if they do, now you have a different occupancy to worry about. In a non-separated mixed occupancy there may be issues with the fire rating for the building. The BO or FM may require fire rated sheetrock and/or sprinklers to keep the garage business from burning up the house.
Electrically, I would have to re-compute the loads on the service. Do you need to upgrade the service for all this additional equipment?