Mesa for stepper based mill

I want to move away from using parallel port based PC's, to do this I am looking at using a mesa board

I have a mill I am considering converting.
It is a 3 axis mill with two steppers on the Y axis.
I hope to have it autohome, auto square etc so will have loads of limit switches, I am aware that I am better off using the dev version 2.8 of Linuxcnc (and the inherent risks).
I would also want to drive a VFD

I believe 7i76E is the appropriate board?

If I wanted to expand to running a 4/5 axis at a later date how/what would I use to expand the set up to cover this?

Comments, suggestions, correction please to my view/understanding/questions

Thanks

The 7i76E supports 5 stepper motors, so should be OK for 4 axes even with a gantry on Y.

There are 2 expansion ports compatible with any of the other 25-pin cards, up to and including 2 more 7i76 (not-E) cards. So that would be 15 steppers, three spindles and lots of IO.

Another cheaper Ethernet option is the 7I96, It does have the disadvantage that it needs linuxCNC 2.8 (master) for full support, but 2.8 may be desirable if you have a dual joint axis since 2.8 allows dual joint squaring natively.