The one outfit I was missing turned out to be Aurora's nude outfit. I had a suspicion it had something to do with her being asleep and stripping her, but there was no way to know how to achieve it without a thorough search of this thread, which in and of itself isn't the most intuitive.
I figured out pretty quickly that saving before you go into the park during the day and reloading if a ! shows up or an event that breaks an attraction or lowers park rating happens was the strategy to keeping park level up. What I didn't realize was that you needed to trigger the negative events on the attractions in order to make the villain cafe even appear, much less the villains associated with them. I spent a ton of time with only Cindy and Aurora fully completed for what I could do at the time wondering what to do next, and even Yen Sid wouldn't help. I eventually just bit the bullet and tried triggering the ! one or two at a time and passing time, after happening to see villains mentioned in this thread and putting 2 and 2 together. That was when the cafe and villains started appearing and I finally got access to more to do. I also never knew at all that you could speed up the upgrade processes at the cost of more money until after I got frustrated and cheated all the upgrades under the false assumption that they could trigger scenes or outfits I was missing.
All that said, this game is fantastic. It's everything my very specific fetish wants from an H-game. The decision to keep the girls' dresses on during the scenes is a great one that very few of these games make. It makes me a little sad that Aurora doesn't like hers, because I love it, but she's so chill anyway it almost doesn't matter.
However, a couple suggestions:
1) please please PLEASE add either a hint system or something to point players in the right direction if they get stuck. I don't have a problem talking to Yen Sid but his dialogues repeat themselves very quickly, making it a bit counter-intuitive to keep talking to him, at least until drawing level maxes and you have nothing else to do with him. Therefore, some form of indicator that you need to talk to him when you need to, or a simple "have you tried x?" can only help new players. You could even give him a separate hint option in his dialog options between "drawing" and "never mind." That would also help incentivize players to talk to him, so they wouldn't get stuck on the parts where you have to talk to him to proceed.
2) the park sim aspect is actually fun, and it feels good seeing the park level increasing, which leads players to want to do what I did and reset often; especially when they realize that dating the girls is dependent on the park level being above a certain threshold. So, could you please make it so either dates aren't based on park level since park level largely doesn't matter anyway besides as a feel-good or a helper to get to 1 million; or make it so the negative ! events on attractions only happen once their villain is implemented and solvable so you don't keep having to eat losses unrelated to something you can fix? It's very easy to get dropped all the way to park level 0 if you're particularly unlucky and don't realize to stop checking the repeated ! events.
Finally, and though probably impossible, if this game somehow ended up with fully animated scenes, ohhh baby. It'd be the best game ever made, for me at least.
Either way thank you and I gratefully await future content.