Cylinder #7 down on compression

I like to smear a layer of axle grease about 1/2 inch down the bore, in all cylinders. Then bring whichever piston up to the top, the grease is to prevent chit/carbon getting between piston and wall.
This is most important cuz any debris, carbon, whatever you scrape off that gets down the crack, stands a chance of getting blown behind/beside the ring on first explosion, and when the ring goes down the worn tapered wall, compresses that chit behind, and can/does jam the ring. When the piston moves down after scraping/cleaning wipe the debris and grease off the cylinder wall, residual grease can remain in the gap, then wipe all before assembly.
I use a sharp scraper, the carbon is usually pretty soft, a wire brush on drill is useful in the valve reliefs.
There is still something funky about cyl #5 difference in appearance.
Maybe scrutinize the intake gskt for vacuum leak, head gasket for coolant loss, not sure from here, lol.
Good luck.