This card combos really nicely with Colossus. Lowers his cost even further, Colossus defends with his Tough status & can be used again later for an attack 3 and another defend. Polaris works well with this card too, she even gives the extra flexibility of allowing the player to choose which X-Man receives the Tough status

Can you resolve bamf after resolving this card? If not why not? According to 1.6 can this card even resolve itself?

From 1.6 Defense:

• • A hero can use their basic defense power to defend against an enemy attack. A hero must exhaust to use this power. The amount of damage dealt by the attack is reduced by the hero’s DEF value, and any remaining damage is dealt to that hero. While a hero is defending against an attack, other friendly characters cannot defend against that attack.

When a card ability says to “declare [a hero] the defender” of an attack, that hero is considered to be making a basic defense.

• • An ally can exhaust to defend against an enemy attack. Damage from the attack is dealt to that ally. While an ally is defending against an attack, other friendly characters cannot defend against that attack.

When a card ability says to “declare [an ally] the defender” of an attack, that ally becomes the defender of the attack.

When a player initiates a triggered ability labeled as a defense—such as “Hero Interrupt (defense)”— during an enemy attack, that player’s identity becomes the defender and is considered to have defended the attack if there is not already a defender.

The player’s identity is considered to be the defender as soon as the defense-labeled ability begins resolving. Abilities that trigger “when your hero defends against an attack” can be triggered when resolving a defense-labeled ability.

Based on the above Either declaring a defender overrides the rule that no other friendly may defend against an attack that is already defended or this card cannot resolve itself - as soon as it is played the Hero should become the defender per 1.6 then the ally cannot defend against the attack.