Solid success today. Received the two new boards on Monday and built them today. Looks really good, the spade connectors are solid and tight, the components all fit.
Soldering it up:
Ran it in the test rig and works!
However still one more iteration. Sharp eyes will see where I had to enlarge one of the notches for it to fit the black plastic housing. In addition, the spade connectors are slightly shifted to the right, by like 0.5 mm. It works, but it ain't perfect. Finally, some silkscreening didn't turn out the way I want it.
These are relatively easy fixes. The current iteration works in general and I'm happy about it.
I am confident enough to now say, folks, we have ourselves here a cold start circuit replacement board built using modern components.
Slightly different design but not horribly so. (I'm still not given up on reproducing the spade connectors.)