I'm not Randy, but..
1) Yes, the Opti-Wiz optical interface that comes with the spinner has inputs for three total axes; one for the spinner and two for a trackball (or other optical devices). You would probably want to order the unit configured to have the spinner on the Z-axis, so that the trackball occupies the X & Y axes, which will allow it to double for a mouse.
2) I don't know jack about Linux, but I know that the OptiWiz requires no drivers under Windows XP- it detects as a standard HID mouse device. If you can use standard HID mice, you ought to be able to use an Opti-Wiz. I don't know if Linux complicates using the Z-axis, but again, if you can currently use the scroll wheel on a standard HID mouse, then the Z-axis on the Opti-Wiz ought to work.
Hope that helps.