LinuxCNC laser cutters and gcode generation

Hi
I have a very modified Denford CNC; I basically threw out all the electronics and replaced it with a simple stepper controller board, and control that via the parallel port using LinuxCNC. I also changed the spindle motor for a much larger Chinese 3 phase motor and inverter.
My workflow is: VariCad (outputs STL) -> MeshCAM (under Wine, outputs GCode) -> LinuxCNC. I'm very happy with this setup. I don't have Windows and only use Linux.

I have just ordered a cheap and cheerful Chinese 40W laser cutter. Once I have demonstrated that it works, I intend to do the same to this. i.e. discard the control electronics and replace it with a simple stepper controller board, and then control the machine using LinuxCNC.

I would still like to use VariCad but this time to produce .dxf files for cutting and engraving. I then need a linux application to convert these dxfs to gcode.
Question 1: Does anyone have any recommendations of suitable linux software that will do this?

Question 2: I have no idea what gcode commands are best/should be used to turn the laser on and off within LinuxCNC. Can anyone help here please?

You may try heekscnc which is a free CAM software for the dxf to g code conversion, this soft is capable of much more though. There is also a Linux version of CamBam which is a great CAM software (not free).

For cutting applications you will not need special commands to activate the laser, it would turn on for feed moves (g1, g2, g3 etc.) And turn off for traverse moves (g0). Linuxcnc can do this by itself.
But all this just let's you cut but not engrave which is an important application of your machine I suppose...

Regards!
Fernando