I have been using Mach and UCCNC with the UC100controller ( I was led to believe it was needed for Mach 3 to run on 64bit machine )
Is it OK to use it with linux or am I better to use just a straight parallel lead .
I don't know anything about UC100 controller. I don't think it will work with linuxcnc as Lcnc is a controller.

Also you can not use Lcnc to control a machine through the USB port.

So you can use a P/port or a Mesa card or Pico.

Have you got Lcnc up and running and found the stepconf wizard ?