Hi,
I'll leave the LinuxCNC questions to those who know more than I.
Mach3, or better still Mach4 can run pulse input servos. Just about all modern servos have Step/Direction pulse inputs and just about any control software
that produces Step/Dir pulses will run them fine. In many respects modern servos work identically to stepper drives, if you can drive a stepper you can drive a servo.
There are still a few analogue servos around. They require (from the controller) an analog voltage, and the controller has to close the position loop. Mach3 and
Mach4 CAN be made to do that, but only at the expense of hardware and simplicity, and overall I would say that Mach3/4 are not well suited to analog servos.
Analog servos, if you can still find them are more expensive than modern AC servos anyway. The only reason you'd shag around with analog servos is if you already
had them and you wanted to re-use them....poor sick little puppy!
You probably don't need that much programming skill to get LinuxCNC to work, this is after-all pretty basic stuff. What you will have to learn is the rudiments of Gcode,i have some programing knowledge but know nothing about g code
all motion control software including LinuxCNC, Mach3, Mach4, UCCNC etc ALL use Gcode. Get used to it.
Craig