Can I apply Vital Strike when making a Grapple attempt to damage an enemy? It seems that I should, as grappling is a special attack that requires a standard action but targets CMD instead of AC, thus making this a standard attack action, but is that really how this works?
And while we're on the topic, what about other special attack options such as the Two Weapon Warrior's Double Strike ability (APG)? With Double Strike you can attack with both weapons as a single standard action. Effectively two standard attacks for the cost of one standard action.
Can Vital Strike be applied to these special attacks or not?
Can I apply Vital Strike when making a Grapple attempt to damage an enemy? It seems that I should, as grappling is a special attack that requires a standard action but targets CMD instead of AC, thus making this a standard attack action, but is that really how this works?
And while we're on the topic, what about other special attack options such as the Two Weapon Warrior's Double Strike ability (APG)? With Double Strike you can attack with both weapons as a single standard action. Effectively two standard attacks for the cost of one standard action.
Can Vital Strike be applied to these special attacks or not?
It can't.
They are standard action, not regular attack actions, which are required of Vital Strike.