Thanks a bunch John! So it looks like:
Pins 1 through 4 are good to go
I 've got to add the battery to pin 6 and tie ground to pin 3,
Leave pin 7 blank (since I won't be using marker lights, which is odd because there are definitely no markers on this tender anyway)
Pin 8 is good
Pull the speaker lead off the existing loco sound ground and connect to pin 9 (does the speaker polarity matter on this? If it does I need to swap 9 & 10 right?)
Pin 10 is good.
Seems like the toughest part will be re-routing the speaker off the PCB ground to its own negative in the tether somehow. I don't have the insert tools to crimp a new pin. I might just run it separately into the loco then.
This is super helpful, and it seems that the basic answer to my question is YES, with a little re-routing, this tender should be OK to use. Speakers are both 16 ohm, and the "linear taper" potentiometer I assume is the same as the "audio taper" in the locosound.
I'll let y'all know how it goes!
