Daddy, I'm a Zombie Scenarios/Headcanons

If You Kept A Diary

Dixie-
She might feel a bit tempted to read it, but wouldn't actually do it unless you were okay with it, as that would be a huge violation of privacy and she doesn't want to make you uncomfortable.
She'd hide it from people if you accidentally left it behind, and she would guard it like her life depends on it.

Isis-
Once you left, she'd immediately be consumed by the overwhelming urge to read it, and so she would. She'd giggle at anything embarrassing or cheesy that you wrote, though she'd try her best(but fail miserably) to hide the fact that she read it.
If there was something extremely serious/dark in there, then she'd panic and try to see if you're alright and what you're doing.
If there was anything about her, then she'd read the entire thing. She's a bit insecure.

Gonner-
He'd do a good job of not reading it, though eventually the curiosity would consume him, and he would flip to the most recent page.
He would laugh to himself about the funny, embarrassing, or otherwise cheesy things that you wrote. If it was something funny about him, then he might laugh a bit and be a bit offended, but he would be flattered that you wrote about him. If there was anything extremely serious of upsetting that you wrote recently, then he'll slowly creep to where you are to nervously check on you.
He may occasionally ask if you're feeling alright or he may crack a few jokes. It depends.

Piroska-
She'd read it immediately, wanting to know what secrets her bestie was hiding. She would giggle to herself a lot at the funny and embarrassing parts and would stare intently at the parts that were written about her. She worries sometimes that she isn't a good enough friend or that you might secretly dislike her actions. If she sees something extremely upsetting that you wrote about yourself, then she'll instantly find you and check on you, trying to hang out and act like nothing happened.
She'd be nosey.

Nebulosa-
She'd keep finding your diary in the library, and she'd keep putting it in the bookshelf until she got frustrated and started to read it. She may stop abruptly once she realizes what it is, but then she would get curious and chuckle to herself once she realizes that she read something silly or embarrassing, and she'd act like she saw nothing. If there was anything written about her, then she would be dead silent as she carefully read everything. If you wrote something particularly concerning, then she would become increasingly anxious and worry about where you are and what you're doing.
She'd read it and then act like she saw nothing. You wouldn't even know.