I finally got it fixed. The switch was a very specialized "pad" switch (multiple switches built into a pad that fit within a cutout on the bottom cushion) that required completely disassembling the seat cushion, positioning the pad, and reassembling the seat cushion/cover etc. The new one was $40 or so directly from the manufacturer.
None of the above pictured switches will work despite vendor claims. The 727A was obviously a limited production, compact model.
If anyone has to do this repair, contact me and I can save you a lot of time and frustration. Removing the seat cover/cushion is straight forward if you know the procedure. After removing the seat cushion from the seat frame, all that is required is a pair of channel lock pliers.