This has become a point of contention in my group, and not a single one of us has any idea what the answer is. The general consensus is that no one knows because no one's bothered to try. I would like an answer please, so that this argument is resolved once and for all and we can all move on with our lives. Thank you for your time.
As both are optional rule sets that are not pfs legal it is not a priority for most. However as long as nether class is not the vmc class in question isee no issues with it. The resulting product could be very powerful and thus unbalanced but no more than a mythic game could be. If you are comfortable with overpowered games then i say go for it.
Gestalt is a homebrew system that will require a homebrew answer. I'd allow it, but I don't have any more backing to that reasoning than your GM would for disallowing it, and your GM has a hell of a lot more authority than me.
Thank you both for your answers, this has helped me immeasurably.