Stand-ins, not blanks.
Give an AI model a sentence with every name redacted and the sense of the original has gone: it has a structure with holes in it, and it will fill them with guesses. Text that is placeholder after placeholder fares little better. So the names you protect are replaced by stand-ins that read like the real thing — a person of the same gender, an organisation of the same kind, in the right form for the target language — and figures by believable ones, scaled consistently. The AI model still reads a document that makes sense, and translates it as one.