If such an ability requires a target, you can target a Room even if both of its doors are locked, but the ability won't do anything when it resolves
The 3-cost Black Sorcery Buried Alive is, er, brought to life in Bring Out Your Dead - because why shouldn't we use the corpses of medieval plague victims to fuel necromantic Black spells
Of course, casting a spell that has transmute certainly counts as casting a spell, though transmute is completely irrelevant in that case
According to various EDH sources, this card sees a surprising amount of play in EDH decks
Garchomp ex #245 Special Illustration Rare : Around $28 Professor Sadas Vitality #256 Special Illustration Rare : Around $28 Parasol Lady #255 Special Illustration Rare : Around $27 Altaria ex #253 Special Illustration Rare : Around $22 Tapu Koko ex Special Illustration Rare : Around $20 Tulip #259 Special Illustration Rare : Around $18 Rika #258 Special Illustration Rare : Around $17 Golisopod ex #246 Special Illustration Rare : Around $16 Professor Turos Scenario Special Illustration Rare : Around $15 Update Nov
I'm not in the business of providing financial advice, but this seems like an easy decision