During Pain's assault on the Leaf, Donzo and the Elders didn't want Pain to get the nine tails to protect the village from destruction. By hiding what he wants which makes him destroy the village.
Danzo did not have any control over Naruto while he was on Mount Myobuku. Danzo did not have an affinity for frogs and he really had no way to contact Naruto. Also Naruto was doing important training there that he had to finish before returning to Konoha. Danzo probably did not want to rush Naruto's training and risk him not completing it.