Finally got around to doing a compression test on the engines. I don't think it looks good but I'm not an engine expert.
Based on those numbers, looks like the left engine on the port side cylinders overheated at some point.
You may be fortunate if they sat around forever without being ran and some aggressive decarboning may help to free up the rings but I doubt it.
If you want a real picture of where things are at without removing anything yet, you would want to get a leak down tester and do a leak down test before disassembling anything.
There's only three places the air can leak out from (the block/crankcase/head, exhaust, or cooling system).
What everyone who actually knows (fastbullet & racerone and a few more) will likely say is at least the bypass covers need to be removed for inspection of piston wall and piston rings.
More likely though the head has to come off and bypass covers to get a full picture.
Take lots of pictures and label them properly on where they are from.