You want to be knowledgeable, likeable, friendly, specific but informative, plus a hundred other things. You have to be able to talk easily about various subjects. Relax enough that you could make the interviewer "Like" you. You must enjoy teaching (or it will be more work than the pay).
Use "Yes sir" not "dude", "I'm sorry, could you repeat that" not "say again" , and "Thank you for your time".
Training centers go through Instructors some times on a frequent basis. I know of a center that lost 14 Instructors in one week. It was not a friendly place to work.
The 1900, metro, and Dash 8 all at once would be rough. I bet they will pick only one for you to work on.