Good advice so far on the interview.
As for the second school, don't even go to that interview. It sounds to me that the guy doesn't view you as a potential employee, he views you as a potential customer, and is using the job as bait. If he had said he really needed an MEI there, and would like for you to get that soon, it would be one thing, but to put the ATP course out there as well means he's not looking for an MEI, he's looking for someone to give him more money than he's going to pay you. Don't give him the time of day.
I'm from Houston, instructed there for a while, which school are you going to that has the Comanche?