you are well organized and approaching this project in the right way.

WD is a good cleaner - it is actually more of a solvent.

I use soapy water (dawn ultra) with a little splash of kerosene in the water

and automotive degreaser for the chain and greasy parts.

hint - on the shifters - get one of those little twist ties that are used to close a plastic bag - and stick those thru the shifter parts as they come off the boss.

the re-assembly and adjustments will be learning experiences. treat yourself to all new cables, housings, and a new chain. Tires too.