You should be in good shape if you already have a good deal of familiarity with some of the software.That said,you till have two new areas in which to develop some further knowledge.Obviously you need to become familiar with getting the machine to carry out your instructions and while you mention Mach 3 specifically,it is a bit dated and other software is likely to work with your breakout board.At some point you are going to have to configure your chosen software to work with the board and you can assign pin functions as you do so,in fact you have to do just that and will be ahead of the game if you have schematics of your hardware.You could take the opportunity to check out Mach 3's newer brother Mach 4 or something like UCCNC.
As for CAM software,you need to check out the post processor options for each package as you will need something that works with your control software.Many of the packages have trial versions that will allow you to gain some experience before you part with money and you might take a look at a few.Vectric is fairly good and you can find a good number of post processors packaged,they also have a sensible upgrade pathway if you need further capabilities.
A vacuum system is a very nice thing to have if you have a sufficiently powerful electrical system.You probably know that it needs a high flow rate and the smallest motor I have worked with for holding down 8X4 sheets had a 4Kw motor-it was just about enough.I also have experience with a 14Kw system and it never struggled.Both of these were three phase systems.