I'm using Mach4 Hobby on a LMS3990 converted to CNC. I purchased the ShuttlePro v2 for a pendant and it all works fine together. My electronics are PMDX-411 and 340. I've never used the Path option in FreeCAD, but Mill Wizard has done everything I wanted, so far. I believe the smaller ShuttleExpress would work as well, but you'd have to ask the guys at Mach4. I only use the X, Y, Z buttons even thought there are many more assignable buttons on the ShuttlePro.
Jim