Where to start with Mesa 7i92 + 7i85S

Generally you would keep the servo drives and the servos.
Then work out what control signals the servo drives require, and choose interface boards based on that. (Mesa is a popular choice, but other options exist)

Due to chip shortage and the shipping hiatus, i would get a Mesa 7i96S and a 7i77, that is the best combo as it can do everything, step/dir and analog control and plenty of IO.
The thing is, they can still be found, so if it ends up needing just step/dir control, you can sell 7i77.
I would not sell.

Thank you tommylight!
That was my guess, but wanted to be sure...
We'll also see what boards are in it and if there's support for them still, I regret not taking a picture when I had it in pieces.
brg Johan