Wow, that's quite a photo collection!

It's interesting how the exhaust valves are not consistantly dirty, but some more than others (EGR). On mine, I also noted that #4 (closest to the firewall) had a lot of gunk, because that is where the oil drains most...and that seal was not even working (the valve guide had dropped 1/2"!). You might want to check the valve guides for any slippage: I understand that was one of the problems they had with these engines. It's a very simple fix, if you can find the right guy who knows his stuff.
[EDIT] Seeing's as your seals are still on there, likely the guides are okay. The valve seals actually seat on the valve guide. It's amazing how much I forgot in the few weeks since my repair.

I used a Dremmel tool with a wire wheel to clean the carbon off the valves. Very few of them would spin freely in the closed position...particularly those whose valve guides had slipped down. I coated the valves with installation oil before putting them back in.

Those seals are a struggle to get off, however so you can, just being careful not to scratch the stem surface: scratches will allow oil to leak down.

My memory is returning to some degree: you put the valve in first, then the straw thing goes on the stem of the valve, then the seal, then replace the springs.

You do the Hokey Pokey and you turn the head around...wait, that's not right...

I was also very anal-retentive about the head bolts: cleaned them off real good, and cleaned oil/Jimmy Hoffa out of the bolt holes. I didn't want any gunkus~funkus affecting the torque reading.