Yeah, Cephe is great, I want to add more interactions between followers but I've just been wanting to add more things to do before doing it. Other than some interactions during some quests and everyone hanging out when you get the monster house property, there's not much in terms of the followers saying or acknowledging anything. The player speaking was something I wanted to add because when in other RPGs that have the PC never talk or react to anything, it feels more, I don't know, lifeless? Like when a NPC is talking to you for several minutes and the PC never says or acknowledges anything and the NPC never acts like it's weird that the person they are talking to isn't saying anything, to me is just odd. I definitely get where you're coming from though, if the PC doesn't ever interject or say anything then it allows you to fill in the blanks with how you would want them to have reacted. Maybe I'll try to have a middle ground and have dialogue options that affect the outcome of a chat. I'll have to have a poll or something later when the game is more popular to see what others would want to see. Believe me, if I didn't have to worry about how the player reacted and what they say it would be easier on me, so I'm all for it if that's what the audience wants.
I can change party members just inserting themselves into your party, I just left it so that some do because from a gameplay perspective there's no downside to having them, it's really just for roleplay. I was wanting to add a yandere character at some point, so they'll definitely just add themselves but that'll make it more impactful if it's the only time a follower does that. The next update is gonna have level requirements for most to have the option to recruit them. Some that also have starting classes will be obtainable from the start, but those that already have vocations, like Cephe being a Pyromancer, will require you to be level 10 before having the option to recruit them.
I'm sure you are among the minority of wanting to have a way to make notes in game, but a quick search did give a plugin that can be used for taking notes on an in game note pad. I don't know if there's a way to add a note to a characters bio directly with other plugins though, I feel like it could be done with VisuStella plugins but I don't know. There would need to be some way to bring up the text entry without it being for a characters name or entering a code.