I personally think you are proposing a backwards step and suggest you stick with LinuxCNC. It took me 30 minutes to add an extra axis. Coolant should not take much longer. Spindle speed is also not that hard but you might have to add something like this https://mesaus.com/index.php?route=p...&product_id=91
The tool changer might be a bit harder but I've no experience.
I would suggest that you ask some questions on the Linuxcnc forum before you go back to Windows..
I have not used Mach but from what I understand if you are using a parallel port, its possible to migrate from Mach to Linuxcnc without changing your hardware so I guess you can go the other way as well.