Tapping creatures to attack with them happens just before any required costs to attack with those creatures are paid. If paying such a cost causes your life total to fall below 6, your tapped attackers will have vigilance, but the ability will have no benefit that combat.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.