@Tom Wrigglesworth, Thanks for posting in Q&A. Based on my researching, it is possible to use Windows Hello for Business (WHfB) to sign in to Windows 10 computers that are hybrid joined. WHfB supports passwordless authentication using biometrics such as facial recognition or FIDO2 security keys. However, it is not possible to assign multiple faces to a single account. Each user must have their own account to use WHfB for authentication.
Hope the information can help.
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