Am I able to use multiple 1password databases in the same account or does each user need to login to their own account?
They would need to sign into there own account as 1Password is not designed for switching databases like that.
If you did try it you could cause issues as the browser extension and the app database may become corrupted or misaligned / un synced due to the change etc. Each time you tried to change a database 1Password would offer to merge it etc. Some one clicks the wrong button and now the passwords of one account get co - mingled with another. * I have never used the merge option, the wife and I share all of our 1Password database but across each others respective user accounts etc. thru a Dropbox shared folder. I could be off on how it works exactly (merge option).
Really its alway best to set up an individual OS user account, that way the user can have there own database etc, browser bookmarks, and the list goes on. This also allows the user to setup there own Dropbox account and maintain it for document syncing etc.
The user needs to understand this, aka the reason behind it and so forth. The user's as a collective need to understand this as well that way they get into good habits of always logging out of the computer upon completion.
I personally have an older friend, and his wife. Whom don't really understand situations like this. So in there case its best for them (Me to set it up for them) to share a login, 1Password database, and Dropbox account.
I think T. Hightower was thinking that you meant using multiple data files in the same OS X user account. We don't normally refer to a Family License as an "account" since 1Password is not a hosted service, but I'm wondering if you just meant to ask, "Can each user of a Family License have different data from the other users of the same Family License?" If that is what you mean, then yes. The only thing that is shared is the license key to register the application. The data file(s) and master password(s) need not be the same across all your machines.
If we can be of further assistance, please let us know. We are always here to help!