I feel like your brake problem is due to a failing booster, if your calipers were leaking the brakes wouldn't stick and the pedal certainly wouldn't be to hard to press sometimes. You should still clean up the area around the calipers banjo bolt and watch for more gunk to develop. As for your starting issue, that could be associated with the main relay. I know that my Honda is prone to that issue, when it gets hot the ignition relay gets pouty. GL sorting it out.