I really like the fact that you'll have to spend time with the three characters. It's a mechanic that could be frustrating or annoying in some games, but in this case it's perfectly logical in the story!
I think each time I'll get a choice like that, I'll try the three options and choose my favorite event from the tree, and try alternating haha!
But because of that, I'm wondering about the romance part. I understand the Set 2 endings thing (and it's a cool idea, BTW!), but if you can't favor one guy over the others, does that mean nothing remotely romantic or hinting at romance happens before reaching Set 2, or some of your choices when spending time with someone would lead to a more romantic relationship, and you'd have to get enough of that romance "points" to unlock the Set 2 ending of that character?
Ah, I'm asking so much - if you think it's too spoilery, feel free to tell me so and not answer that!