You haven't really provided enough detail to answer this. Providing more detail would help. Right now I continue to make guesses as to what you need and want to do.
I have assumed a while ago that you have 2 phones with identical photos and contacts on each phone and that they using the same Apple ID.
Is that correct?
If so, backing each up will simply reproduce the content on each when you restore. Getting you right back to where you are right now.
Using iCloud for backups ties the backup to an Apple ID, so you can't back up John's phone and restore it to Mary's. Even if you removed some of the content and then backed up, you can't sign out of iCloud to do th "other" backup without removing all of the content.
It needs to be done manually.
When you back up a phone using either iCloud or iTunes, the backup is a closed file, and you can't go in and remove content from it before restoring.