welcome. as you're a car enthusiast and quite clued in on electronics and OBD-II fault diagnosis, i hope you will find the maintaining the Astra easier than it was for your mum. i'm shocked that all those components have failed at only 81500km.
interestingly on my Barina SRi, i have also had the coil pack fail, the ECU fail, the air compressor fail, and the thermostat fail. coincidence, i think not to be fair, on my car they started failing at 120000km+.
next thing to watch out for is the cam sensor, which will probably require replacing at the next timing belt change.
good luck and enjoy your time at Opelaus