If he is playing Living Wish in a deck with sleeves, he should be carrying sleeves in case it ever goes to a hidden zone (which can very probably happen).
The answer is, he's playing Living Wish and he should be prepared/know better.
EDIT: If you're really desperate, I would recommend unsleeving a card in a non-hidden zone to sleeve the newly-hidden card.
Going a step further, and somebody can correct me, but even if that ruling clarification were not made, and even if the abilities were not "linked," this still wouldn't work.
Spy Kit would give Carrion Beetles the name "Arcane Savant" when on the battlefield. The permanent would have the name Arcane Savant. But it still wouldn't be "A card named Arcane Savant," would it? The card itself is still named Carrion Beetles.
Sadly for you, Wrath of God will resolve and your Sanctum prelate will be dust. Sanctum prelate prevents certain cards from being cast, which is an action that moves a spell from the hand to the stack. Once Wrath is on the stack, the casting is complete, and it is not until after this point that your Prelate is on the field. Prelate says nothing about preventing spells on the stack from resolving, so Wrath will resolve as normal.
Join the Ranks is terrible. You are better off replacing them with March From the Tomb, which allows for some nifty combo kills. Kalastria Healer is probably the best new ally for your deck. I would probably eliminate the Hagra Diabolists to bring your mana costs down and shirnk your number of answer cards in favor of having more allies. Lantern Scout would probably good as a one-of in the mainboard, with more copies in the sideboard to fight Burn. Zulaport Cutthroat is a strong ally, but it triggers differently than your other allies. Ally Encampment is really cheap right now and would help your mana base a great deal.
Respectfully, this is actually all around bad advice and you shouldn't listen to it, except for the part that suggests trying out March From the Tomb (although I suspect it costs too much for what it does) and Ally Encampment. Hagra Diabolist is the best card this deck has going for it, much like Gary, it is the card that finishes off your opponent.
I have to advise against putting any lifegain cards in the maindeck. It's okay in the sideboard against another aggro deck. You are playing aggro, so giving your creatures lifelink and gaining life - not really worth it. I've seen games lost because players are playing cards that are gaining them life instead of finishing off their opponents.
Cut the Halimar Excavator. Mill is not your wincon. Fill it with more aggro guys.
Join the ranks is good because it gives you double triggers, but it's expensive, and maybe the new Gideon would be better?
I question Mana Leak in a deck that wants to drop dudes and swing.
The answer is, he's playing Living Wish and he should be prepared/know better.
EDIT: If you're really desperate, I would recommend unsleeving a card in a non-hidden zone to sleeve the newly-hidden card.
Spy Kit would give Carrion Beetles the name "Arcane Savant" when on the battlefield. The permanent would have the name Arcane Savant. But it still wouldn't be "A card named Arcane Savant," would it? The card itself is still named Carrion Beetles.
My hero! *swoons*
Respectfully, this is actually all around bad advice and you shouldn't listen to it, except for the part that suggests trying out March From the Tomb (although I suspect it costs too much for what it does) and Ally Encampment. Hagra Diabolist is the best card this deck has going for it, much like Gary, it is the card that finishes off your opponent.
I have to advise against putting any lifegain cards in the maindeck. It's okay in the sideboard against another aggro deck. You are playing aggro, so giving your creatures lifelink and gaining life - not really worth it. I've seen games lost because players are playing cards that are gaining them life instead of finishing off their opponents.
Cut the Halimar Excavator. Mill is not your wincon. Fill it with more aggro guys.
Join the ranks is good because it gives you double triggers, but it's expensive, and maybe the new Gideon would be better?
I question Mana Leak in a deck that wants to drop dudes and swing.