We tried something similar years ago with DocuSign, and needed the ability to sign in person with two different people, one acting as a witness, with a potentia

We tried something similar years ago with DocuSign, and needed the ability to sign in person with two different people, one acting as a witness, with a potential third person being remote via email. It was not supported at all. Built our own internal system to handle esignatures, worked great, never looked back.