Unfortunately I think a lot of encounters in his have prerequisites, and then after you meet those it's still RNG whether you get them or not (or at least that's what it appears to be). It took me a month and a half in game time to get my clothes stolen to do the BFF storyline without the quad party. And then another week to get the sleepover event.
Would be nice to have a counter of sorts. First time you go into an area where an event can happen, you have a 1/20 chance to trigger. Next time you have 1/12, then 1/10, then 1/8, 1/6, 1/4, 1/3, 1/2... or something? I haven't looking into the code though, so I don't actually know how event triggers are dictated. Have you been to the discord server? The staff there may be able to provide specific info about how the events work.