On the JM and Jag, the upper slide switch engages the "rhythm circuit" on the neck pickup. This has its own volume and tone control, which are the two roller wheels you can see next to it. It's much darker than the standard neck pickup sound, but I've found it useful at times. These controls are independent of the main tone and volume knobs.
On the Jaguar, the three lower switches are, from left-right: Strangle Switch (it's a high-pass filter, which takes out a fair chunk of the bottom-end); bridge pickup on/off; neck pickup on/off.
I have a few more Fender offsets. There's a couple of Japanese Jazzmasters, a Pawnshop Bass VI and a '65 Electric XII. Oh, and a Jazz Bass! Guess what colour that is....