Remove the pot and switch access cover. A squirt of CRC Electrical Instrument Cleaner spray into the volume and tone pots should do the trick. Same with the instrument jack. Also check the soldered connections are still clean and uncorroded. Hit them up with a light wire brush and that CRC cleaner spray if so. CRC also do an Electrical Instrument Cleaner and Lube spray which will also work. Best in the market and non corrosive.

Can't help with your footswitch question. Guessing it'll be a proprietary wired (then) Rick accessory. Someone here who's a vintage Rick afficionado will know, or try Stephen in the Ask a Guitar Tech Forum.