Also will a flying school want to employ someone with ATPL,Instrument rating & MCC.Surely they will realise you'll "be here today gone tommorrow" after building up a flying programme with them.They may even try and tie you up with a contract.(Not sure if they can legally do that though)
I know of two Instructors who joined a flying school with all the Airline qualifications ,built up good flying programmes then left after a couple of months to the disgust of the flying schools directors.Still the number 1 rule is LOOK AFTER NUMBER 1.
Just be very careful what you say at the interview at the flying school(when you get one)Obviously if you do decide to do IR& mcc then get a job instructing job then dont say you are looking for an airline job.Lie a bit.