There is a Teac 1/2 " that does 8 tracks, you could probably read them one track at the time by judiciously jiggling the height of the head relative to the base of the player. The heads are narrower than a single track so that should work. The analog format is likely simple FSK or some variation on that theme.

It would take 7 passes to get it off assuming only one of the heads lines up with a track at any given time. Keeping the sync between the tracks will be the hard part. I'm in Europe so that probably rules out collaboration on this but if there is some way to get me a sample of such a tape I'll be more than happy to give it a shot.

edit: this machine: https://soniccircus.com/product/teac-80-8-1-2-8-track-analog...