"MAN, I really talk a lot sometimes" you're talking to someone who talks so much I wrote a whole game - you're in good company lol
I'm glad you're enjoying! There's technically a discord server, but it's not in use. I figured I'd wait to see if the game got an audience before really diving into it. So TBD on that!
April and Autumn are going to be Chapter 2 characters, so you'll meet them in Spring of the school year, along with a couple other new characters!
You will absolutely get to know Lizzie better - she becomes more involved in v0.03 :D
You'll totally still interact with Aarya moving forward - her first solo event is also going to be in the upcoming content update, v0.03! Your interactions with her will vary slightly depending on what choice you made at the party, but ultimately, choosing one way or the other doesn't stop you from forming a relationship with Aarya.
There will be path divergences for some characters, specifically within the development of your relationships with them. For example, whether you choose to help Mariah at the party or go home with Aarya impacts your relationships with the people around you - Mariah, Caitlin, Aarya, etc. - but that won't really impact the overarching story. The story itself will be pretty much the same no matter what choices you make, though specific conversation pieces and side events will vary depending on the choices you make (though only the big ones, which don't happen that often, and I think it'll be pretty clear when they matter).
On the topic of soccer, good question, potentially complicated answer. For right now, the wins and losses are pre-determined and happen automatically once you complete a certain set of events (the Hints screen should walk players through how to get further in the game and trigger the next soccer game on Saturday mornings). I have ideas about what the soccer season will look like in Chapter 2, but I haven't made the final decision on whether your choices will impact the outcome of the bigger games later in the story. On the one hand, I think it's fun to give the player agency and reward them with success if they "play well". On the other hand, I don't want people to be 8 hours into playing and realize they didn't get enough points in some random category and now they can't win a big game or something. Because that would frustrate me as a player. It may play a part later in the story, I haven't gotten that far out in planning the details yet. I have a rough outline of the rest of the game, but that decision is still a ways out in development lol. Chapter 1 probably won't even be finished until like March. I'll probably make a decision on that stuff then!
So the TL;DR is "right now soccer games are all pre-determined, but that may change in the future if I can find a way to make it feel both fair and rewarding".
Hope you keep playing and continue to enjoy :D