One thing you could do is to use Bitwarden’s Password field to store the “memorable word”. Then, after you toggle the visibility of this “password”, you can click on the 
icon, which will show the numerical position of each letter/character in the password.
This leaves the issue of what to do with the actual login password. You can create a custom field of the “Hidden” type to store the password. If the password input field on the login page has a unique ID or name, then you can set this as the name of the custom hidden field, which may allow you to auto-fill the password (YMMV). If auto-filling can’t be made to work, then you’ll at least be able to copy/paste the password.
Another work-around is the one described in this comment and this comment by @danmullen.