OK, I'm happy to report that after driving over 200 miles and readiness is set - there is no CEL.
All I did was replace the rear O2s (after they were destroyed in the removal process); remove the Cats and replace with a straight pipe, drill a hole into them, weld the spark plug non-foulers to the pipes and screw the O2s on them.
Maybe many more miles will cause a CEL - I don't know but for now it is looking very good.