I've got a stock /6 from '69 that has spent a fair time (35+ years) sitting in a garage.
I've been diagnosing bending push rods on the 1,5,6 intake valves for a bit now.
So I pulled the head and those valves were stuck tight and the seats full of thick sludge.
I've kindly received a new, built, clean head from the Legendary Lou Dart270 and was ready to drop-in replace.

But upon the final inspection, I noticed that the lifters for those exact valves were stuck "lifted/up".
I sprayed some Kroil and got them loose and spinning freely when spun with a needle nose.
I spun over the engine a bit and noticed that a few of the lifters were either rotating very slowly or not at all - including some of the ones that weren't even stuck prior, and that spin freely when rotated manually. All lifters moved up and down as the engine cranked, but some just wouldn't rotate at all during the up/down motion.

So, I tried to pull one of the offending lifters (exhaust cylinder #1) with a needle nose by its top "lip" a few times - and it rose, but only a few mm higher. THEN I took a break, and came back to find that I must've gone at a bad angle earlier or something; because the lip was cracked! There were some metal bits hanging out in the valley area that I had to pull out with a magnet at risk of having them drop through the oil hole...

A few questions and open to additional comments:
1. Anything more I should consider investigating due to the lack of automatic lifter spinnage-on-crank?
2. I assume I should be replacing (at least) that cracked lifter. What is recommended in terms of the replacement? And should I be replacing them all once I'm at it?
3. Is freeing the remaining lifters as I had done above (Kroil method) enough to button up and continue installing the new head?