WOW !
That's one hell of a job ahead of you - but take your time and it will be the centrepiece of your collection. If this is the Holy Grail - don't be afraid to spend some serious $ as it will keep it's value.
IJ "BAD" playfield - Use this to practice touch up work.
IJ "GOOD" playfield - Use what you have learnt and apply to this playfield. Alternatively, send the playfield to TIM at HRP. Touch up and clearcoat will be the best there is out there !
IJ Cabinet VS Popeye - Don't part out Popeye. This can be saved. Look at a NEW cabinet from HRP - New decals with a finished cabinet to match the playfield and you will be amazed !
OLD parts - get them replated. No need to buy everything new !
This is a really interesting thread - so keep the updates coming, and ask as many questions as you like to keep the ball rolling !