That's not how I see it. If someone concedes he concedes. There isn't anything someone can do against it. The only thing that can be done at this point is to haggle about the conditions of the concede. If someone could just veto the concession, then the hole concept would be meaningless.

Actually, it depends.

If it was ranged incite emotion, then the target may be dead, insane, dominated or similar but the vampire cannot have fed.
if it was melee incite emotion but the vampire did not double the attack into a feeding, then the results are as above and the PC either forgot or chose not to feed.
If it was melee incite emotion and the vampire doubled up the attack into a feeding, then the target is dead and the vampire gets free recovery.

My take on the Fourth Law issue:

You didn't force people to change their mind, implant thoughts or emotions, you just stopped action.  No more harmful than a "Bigby's Grasping Hand" force style spell.  No Laws broken even if it were purely mortal magic.

You didn't even stop them from being upset that you stopped the action or interfered with their ability to want to commit harm, you just them from being able to.

Here, enthralling is any effort made to change the natural inclinations, choices, and behaviors of another person.

But with respects to the White Council, as the Warden on the scene, he gets to decide.

A debate was sparked post-game:  Does this spell break the 4th Law???  It seems to suit the theme of soulfire..being all peaceful and such

A slippery slope to an unbelievable narrative and characters who are never challenged in combat.

@WillH;
Your method has the reverse problems artificers have...