If Champions of the Shoal is countered or otherwise fails to resolve, the beheld card will remain in exile indefinitely.

One or more stun counters on a permanent create a single replacement effect that stops the permanent from untapping. That effect is "If a permanent with a stun counter on it would become untapped, instead remove a stun counter from it."

If a card in your hand is already revealed (perhaps because it was revealed to pay a cost of a spell that's still on the stack or due to the effect of a card like Telepathy), you may reveal it again to pay the cost of another spell or ability that requires you to reveal a card from your hand.

If an effect refers to a "[subtype] card," it refers only to a card that has that subtype. For example, Glen Elendra's Answer creates a Faerie token and features a Faerie in its art, but it isn't a Faerie card.

If a cost to cast a spell includes revealing a card, that card remains revealed from the time the spell is announced until the time it leaves the stack.