Mesa 7I96S and closed loop/linear scales

You will need more than just a 7i96S if you want linear-encoder feedback to LinuxCNC as the 7i96 only has a single encoder channel (generally intended for use by the spindle). Maybe a 7i85 or 7i85S on the 7i96 expansion connector.

Linear scale feedback to LinuxCNC can be used to compensate for machine backlash, deflection and nonlinearity. If integrated into the drive encoder feedback on the motors can be used to control motor position and intelligently control the drive current.

So, ideally I think you might want to look a the integrated closed-loop stepper motors (and just let them do their own thing with the motor encoder feedback) and then use the scales to modify the position commands sent to the drives based on the actual measured position.