The hard watchdog should be rarely needed if ever and i believe piaware already sets the watchdog, but that only triggers if the Pi really locks up which should be rare.
For the most common stuff i have done scripts:
dump1090-fa hanging reset script:
(Dump1090-fa stops sending messages after some time - #12 by wiedehopf)
Resetting the network when that fails:
(Feeder Outage: PiAware 'anyname' is not sending ADS-B data to FlightAware - #4 by wiedehopf)
So i guess you are mainly posting here to get it integrated into piaware?
Because those scripts are actual solutions to your problem.
Have you actually using both scripts?
As i wrote before the network thingie can just as well be written so that it reboots.