1. There's alot of advice and information available in PPrune forums already on these subjects. It would be beneficial for you to learn the search features available in PPrune, so you can see what has gone on before.
2. Please don't be an instructor because you can't think of anything else to do while you wait to become an Airline Pilot.
Who wants to be taught be someone who isn't interested in the student's progress or in teaching generally?
You need to examine you motivation to teach. If it isn't there, please get a job doing something else, but which will allow you to save money to get the various licenses & rating you needs, keep current, and stay in touch with development in the industry etc.
3. The feedback on PPrune suggsts a lot of people are going to be looking for instructors jobs until the industry picks (as it will). If you do go down the instructional route, you'll need to be sure that you can differentiate yourself in the marketplace. Can you?
Remember that a Flight School's ideal instructior is someone who live and breaths flying instruction, has bags of hours/experience/rating and will work for nothing. How close to this are you?
4. Persistence pays off. Well done getting as far as you have with BA. It can't have been easy. Keep the faith, and stick with it.