real person - 60 Halloween Costume Ideas
These costumes copy actual people instead of fictional characters, Taylor Swift's stage outfits, Kitty Oppenheimer's 1940s style, Nicholas Cage playing an exaggerated version of himself. Real photo references exist for all of these, which makes accuracy easier to check.
Recognition depends heavily on how well-known the person is outside their most famous moment. A recent viral look reads fast, an older reference might need a bit more explaining at the party.
Not exactly, get the signature styling and one or two defining features right and the costume reads fine.
Most are currently well-known, a few lean more niche. Check the specific guide for how recent or famous the reference is.
Generally yes for a costume in good taste, it's the same as dressing as any public figure or celebrity look.