My new Mac Mini asks for a password that doesn’t exist! Now my other devices do, too.

Bought a new Mac Mini to upgrade from the old iMac. Signed in with Apple ID, and created two user logins for hubby and me. These are the only passwords we have. Now it repeatedly asks for my Mac Mini password. It does not accept either the Apple ID password or the user login password. The only way past this is to say I forgot the password and then it says I must reset encrypted data. So I do that and all appears well. Except now the old iMac asks for the same, and then the iPad. Each time I do the reset encrypted data. But at some point one or more devices will ask again. What is this password!? I never set up a Mac Mini password, only the Apple ID and user logins.

On another note, the new Mac is showing my husband all my photos and emails! Even though we have separate user logins. Yes, we share my Apple ID but we always have and this never happened before. He deleted bookmarks in Safari and now they are gone from my iPad, too! I have bought Macs all my life but these frustrations are driving me mad. Thanks for any help!