As mentioned above you will need quite a bit more to run the older cRio.
If you are looking to run an alternate solution I would suggest the Vex Cortex which will work quite easily with the existing motor controllers. It will be wireless without having to add all the additional electronics that the cRio system will need. Plus it has a much smaller footprint.
You will need to use a PDP board and such for the power end..
To answer your question..
You can use just about any PWM controlled motor controller available.
Such as the Victors, Talons, Jaguars.. It will need to be run through the sidecar which will need the cRio to have the NI 9403 digital I/O module installed.
Here is the wiring set up from 2014 for your reference.
https://wpilib.screenstepslive.com/s...control-system
Note the difference between the cRio in the above set up link and the FRC 2 version you have is the amount of slots, 8 versus 4.
If you want additional information on switching to the Vex system let me know. We used to run it on our practice / previous years robots.
Good luck with this project,
Aloha!