Right everyone does it differently, it can get plenty cold in Ohio for winter too but even the coldest winters still have days that get to the 40s or and occasional 50s so that will be the days l choose to start and run the car for 30 or 40 minutes. I sent an oil sample to Blackstone a couple...
Your description of "Squishy" to me means you have air in the system and it needs bled. It would'nt hurt to do a full brake inspection to see which parts need replaced.
I knew I had read it in the Owners Manual before so l dug it out today and listed under "Storage", it says every 15 days but I just usually do it once a month or so.
Been doing it with this car for 23 years and live in the cold too, in fact the Owners Manual for the car tells you to do it that way. Got 11 years out of my last battery too, was never on a battery tender.
I dont ever bother disconnecting my battery, when the car is stored for winter I will start it up once every month or so and let it run up to operating temperature.
I have an Aftermarket Coil in my car, think its MSD. It also makes a weird electrical type buzzing noise too, but its been in the car for about 20 years so it obviously doesnt hurt long term reliability.