Even threaded shank cutters have enough plain section for a collet to grip - haven't had a problem (although most of my cutters are plain shank anyway).

I have a Warco VMC, broadly similar to your machine; I flip the lid open and hold the pulley to "lock" the spindle and that's always worked OK for me.

DRO's are great. I doubt if I've looked at a dial on my VMC more than a half-dozen times since I've had it. No more losing count when you are moving a couple of inches, trivial picking up centre lines with a wiggler, etc.