There are no character meal specific buses. But, to get to Chef Mickeys for 7:30 you should be out at your bus stop at POP about 6:30-6:45. Yes, the buses run that early. You will take the MK bus. When you get to MK you will walk over to the CR via the sidewalk. As you get off the bus, go towards the front of the park, but when you get to the end of the bus driveway, go right. It will be like a U. The CR sits at the top of the U, with the bus stops at MK being on the right side of the U, and the sidewalk to CR on the left side. It takes about 8 minutes to walk to the CR from there. If you get lucky, the driver may ask where you're going and then drop you at the CR, but I have never had that happen.
I say to be at the bus stop that early because if you just miss a bus, you may have a 20 minute wait for the next one, then it's about 15 mins. to MK, then an 8 min walk....better to be early than worry about being late.