If a face-down creature loses its abilities, it can't be turned face up with a disguise ability because it will no longer have a disguise ability (or a disguise cost) once face up.
Mistway Spy
If a face-down spell leaves the stack and goes to any zone other than the battlefield (if it was countered, for example), you must reveal it. Similarly, if a face-down permanent leaves the battlefield, you must reveal it. You must also reveal all face-down spells and permanents you control if you leave the game or the game ends.
Because face-down creatures don't have a name, they can't have the same name as any other creature, even another face-down creature.
Magic: The Gathering · ™ & © Wizards of the Coast · Illus. Andrew Mar
Card data via Scryfall. Rarix is fan-made; not endorsed by the rights holders.
