Help Implementing Adapted Stepper Driver Control

The issue isn't the unipolar/bipolar difference, the issue is the number of poles of the motor (which for steppers is usually specified as steps/revolution). If the two motors are the same, and if the new board is clocked the same, then you're probably OK.

One generally uses steppers _because_ one wants to avoid using feedback, so this isn't surprising. Most likely the antenna board resets a reference to zero when it gets the index pulse, and increments it by

What kind of help? Technical? Psychological? Aesthetic?

If you're unlucky enough to not have a 32 step/rev motor, but you do have some easy multiple thereof then you just need a micro that'll issue one step for every two of the input, or two steps for every one input, or something like that. If you're unlucky then you may need something like a PLL-based frequency synthesizer that'll generate the correct number of steps for your motor from the number given -- if it came to this it could even be something like a 4049 and some counters, although you could do it in a micro.

If the driver board you have supports microstepping it'll be easier to make a mis-matched motor work.

I hope this helps.