2022-12-08 : A noncreature permanent that becomes a creature can attack, and its {T} abilities can be activated, only if its controller has continuously controlled that permanent since the beginning of their most recent turn. It doesn’t matter how long the permanent has been a creature. Notably, if you turn Nantuko Monastery into a creature on the turn it entered the battlefield, you won’t be able to tap it for mana.

2022-12-08 : After it becomes a creature, Nantuko Monastery will still have all its abilities.

2022-12-08 : Once you activate the last ability, it doesn’t matter what happens to the number of cards in your graveyard. Nantuko Monastery will remain a creature that turn even if that number falls below seven.