I'm not sure if what I'm going to suggest is the second point here, but:
For me, the desired way to do it would be for a team member to generate a separate keypair, they'd give me the npub, and it'd put it on a list where to see their sent notes to me, for me (the main npub) to publish manually or automatically.
This can be a client function or a separate nip function (with a supported client).
This removes any complicated setups and decrease a lot of risk.