I contacted Xylotex Support via Email and he (Jeff) told me that my Engraver steppers will work with their 3-axis controller, so I went ahead and purchased the controller and a 24V power supply. After I receive the controller I'll have a ton of work wiring up the 3 steppers and 5 limit switches. I'll also need to define an M-code for spindle on/off and wire in a relay. I'll post more comments here as I get more into the project.
If anyone else reading this has experience using MACH with a New Hermes engraver that you converted to CNC from the original dedicated controller, please tell me about it. I'd like to learn from your mistakes and successes!

Thanks!