Check with Bill Hirsch Auto they sell engine paint and may be able to help with what the correct color should be for that year and engine, https://www.hirschauto.com
Checkout Classic Generator, www.classicgenerator.com , they restore generators and also sell repair kits and parts. They may be able to help with your generator.
Try Fender Skirt Depot, www.fenderskirtdepot.com , they have reproduction fender skirts and some original fender skirts. Might have some for your Pontiac.
Here are a couple of places that can rebuild the pump if you have one.
Arthur Gould https://agrebuilders.com , Flying Dutchman. www.waterpumps.bizhosting.com
O and G Waterpump. https://www.oandgwaterpump.com
Check the Lincoln / Mercury page on https://www.vintagepartsource.com , there is a good list of Mercury parts suppliers that will have some of those Cougar parts.
If that switch does not fix the problem you can try Classic Generator, www.classicgenerator.com , they rebuild these units and also sell parts for them.