You can change the names of your profiles on your account page. Log in to your account on the BookBeat website. Once on your account page, you will find the "Profiles" section in the menu.

Here you can see all your profiles. Click the pen symbol next to the profile that is due for a name change. Enter the new name and save. You can also change the first name of your main profile here.

At the moment it is not possible to change the profile picture / avatar for the different profiles.