I have my CCleaner set to erase nearly all listed files since, well, since they just annoy me. On Edge and IE there's an option to clean the password files. My, probably, stupid question is this; Will adding the password files in Edge and IE to be deleted each cleaning going to affect the passwords in Firefox which I want to keep and is unchecked. I really hope this made sense.
No it won't.
But you may not want to be be clearing 'Saved Passwords' anyway.
Those are the names/passwords that you save in a browser if you want to be able to click login and have your name and password automatically entered.
It's not something that you need to clear everytime because you don't save passwords all the time (which is why it's not ticked by default).
If you do clear 'Saved Passwords' then you will have to type in the name/password manually when you want to login to a site using that browser.
I think that what you may be thinking about is staying logged into a site when you close/reopen a browser?
In CCleaner's Custom Clean that is 'Session' for the browser, (or for some websites may still be a cookie).