You are certainly on the right track with Linuxcnc and Mesa.
The Mesa cards have many options so it should cover all your hardware.
With regard Plasma, the new Linuxcnc QTPlasmaC configuration is the ducks nuts. I just did a video outlining its features on the weekend
Best bet is when you know a bit more about your machines is to post on the linuxcnc forum and you'll get great support. User PCW is the owner of Mesa and is tireless on that forum so you will get excellent support re hardware selection
I'm in Brisbane BTW. If nearby feel free to contact me. I don't mind visitors.