What are the limitations to the actions a unit can perform via General initiative commands?
As long as it does not otherwise violate the rules for actions, none.
Oh, and if the VOF exceeds even the max -4, does anything worse happen? For example, I had a unit with -6 total VOF yet -4 yielded only a pin. Does it bump to a hit if it goes off the card??
The Minimum NCM is –4 and the Maximum is +6. A NCM of less than –4 is considered a –4 and a NCM greater than +6 is considered a +6.