In a perfect world one of
Johnny/Sarah/Britnee
will win POV and double save the other two. I don't know who the HOH will replace them with, maybe
Pilar and Kevin
? The HOH has no other choices, really.
I think Double Veto means a POV Competition with TWO vetos.
I understood it as the veto comp winner gets two vetos to be used on both nominees.
EDIT: Nevermind, I think you're right. The website days "Houseguests will have double the chance for veto power". I guess that's still the better option though.