RE: Wounds & Vitality, I can at least tell you how I've been running spells and sneak attacks under this system. I see a lot of people suggest converting attacks that deal dice of vitality damage into "1 point of wound damage per die," but I find that to be a pretty inelegant solution -- it loses the distinction between die types, for starters. So, I just used common sense for sneak attack and applied the rule that was already there: damage expressed as extra dice, such as from a sneak attack or an elemental weapon, is not multiplied by a critical hit. Therefore, it would stand to reason that under a VP/WP system, such damage would not change to wound damage on a critical hit, and would instead remain vitality damage.
For spells, I just took an alternate route. At the moment, I'm ruling that when a spell or similar energy effect critically hits, some of the damage becomes wound damage -- an ammount that cannot exceed the spell's level (or, if the effect has no level, 1/2 the hit dice of the creature using the attack). So far this has worked out well, but if it proves to be on the weak side, I may just change the wound cap to caster level (or, if I like the UA rules, "magic rating").