Wow! Lots o questions!!!

A few answers.

I wasn't using much oil, less than a quart between changes. I had several leaks developing that needed attention. My compression was 155 to 160 evenly distributed. I didn't do a leakdown on all cylinders. I did on the one cylinder that had a funky plug last tune up. It was ok, no leakdown overnight.

I had been running 91+ fuel to limit a bit of spark knock at higher elevations on long hill climbs. I also advanced the timing slightly for more pep from the added octane. With the spark knock came a little higher temps on both temp gauges (OE in the IP and Autometer on the dash). Nothing that was not controlled by the fan thermoswitch and the Taurus fan.

I've been running regular green at a roughly 50/50 mix with distilled water. I've done major flushing on the engine several times. Wasn't really expecting to see as nasty water jackets as I saw.

I had planned on doing an oil pan gasket during all this, should I proceed with that and pull off a main cap and see what the bearings look like?