yep reason i suggest the coil/imob is because i had a starting issue recently and after going over pretty much the same items you have it turned out that the imob was the issue. it could actually be the coil itself because if it was anything mechanical you would have heard some weird noises when it cut out.
So many many times over the years i've heard garages say it's an ECU problem even with the bikes. Never was so! : The ECU will be a problem if you TAMPER with it!