Can I use a crêpe pan instead of a comal?
Based on personal experience: yes.  I'd recommend the frying pan over the crepe pan, because the frying pan likely has a thicker bottom and can just be left on low heat for an even heating surface.  Rolled steel crepe pans develop hot spots if not moved around.  In either case, you heat the pan dry.
Better than either of those, however, is a griddle.  You can cook up to five tortillas at a time on a large griddle, whether electric or cast iron.  I make corn tortillas at home, and I always use a nonstick electric griddle for them.  Since it takes just about as long to press out a new tortilla as it does to cook one long enough to need flipping, I can get a real production line set up, and make 20 tortillas in less than an hour.