Player-specific notes for characters they are unable to edit

As is, if a character is in a players journal but they are unable to edit it, there is no place for them to write down any information about that character. And, if they CAN edit the character, all that information goes to anyone who looks at the entry in their journal. For me, this would be helpful since my players could jot down small pieces of information that a recurring NPC divulges. Everyone picks up on different things, and having a place for notes for each character that is specific to each player would be useful.

I generally create a handout for each of my players that can only be edited by each.  While that doesn't give a note space on each npc, it might be useful to you if you aren't already doing something like this.  I also make one the whole group can see and edit for shared resources or information.

I encourage my players to place [brackets] around any proper nouns they mention in their journals so that I may create handouts and provide them links to NPC character sheet bios and handouts. What ends up happening is that they slowly build up a Wikipedia of character knowledge in their bio with links to other characters and handouts, making every character unique in their knowledge of the world.