Nope, there isn't a guide. I'll eventually be working on some sort of hint system to help people get them all. For now I can just tell you what you have to do for each character.
For the Kobold there are 2 scenes, one where you need to be small (have stats close to when you start the game, you can maybe use a tiny elixir or a yellow berry to help with that) and one you can get if you wear the hat you get from the cobra
There are a few scenes at the Unholy Hollows and to get there you need to get the Giant Werewolf's business card. The way to get it is different depending on your species. You'll need him to confide in you about how he feels about humans and to do that you'll likely need to get him his moon artifact from the temple, remind him that you were the one to give it to him, and then talk about his tie
There's a scene with the cobra if you try casting the Spell of Love on him
To get to the scene at the shark's place you have to talk to the bat and shark at the bulletin board at night with at least one of them interested in you. For that to happen you either need to flirt with the shark and then apologize to him or talk to the bat about something he's interested in and then ask him to do something else once he's at stage 3. After the scene with them together you can get scenes with them individually by repeating the things that got them interested
For the knight - if he's low level and you go to the gym you'll find him there. If you lift enough weights in front of him he'll be impressed then in battle you can get a scene if you compliment him then grapple him. If he's too high level to find at the gym you can take an empty XP bottle to the turtle to get a black XP potion that will set him back to level 1