As a sign of friendship, Urza gave the healers of the city potent amulets
Saga creatures follow all the same rules that other Sagas do, writes WotC's Matt Tabak in the official article about Final Fantasy x MTG mechanics, and is also a creature and can do everything a creature can do. Simply put, summons are three types of cards (enchantment, creature, and saga) rolled into one
However, if that sells, the remaining available one will be nearly double that
That means the prices for such cards jump immensely in price
Equip variants or equip abilities with restrictions, like the "equip legendary creature" ability of Brotherhood Regalia, are still equip abilities, and their costs will be reduced by Bureau Headmaster's last ability
This means that, unless you kill off a ton of creatures on the turn you resolve this card, you cannot play it