@Shimae0
I have had similar issues with guest smoking weed in my private room listing. Of course, there is really no way to submit hard evidence of this. What I did in the claim, was determine everything that required additional cleaning (drapes, carpet, down comforter dry cleaning, etc) then I went online and got quotes for all that and submitted the quotes. Airbnb reimbursed me each time. As for the additional guest, again that might be hard to prove as it comes down to a she said he said type of argument.
Moving forward, I would suggest the following:
-Install some form of doorbell camera. This will allow you to monitor your guest's coming and going and allow you to know if they bring unregistered visitors. It also allows you to address these issues closer to real time vs finding out upon check out.
-Re word your rules regarding check in windows. I was a bit confused about that when I read your listing and your complaint here. It sounds like your check in time is 3pm-2am. However, it also sounds like you don't allow guest to enter the home after 2am during their stay, meaning essentially, they have a curfew? If I interpreted that wrong, I apologize. It's reasonable to have quite hours, but it is difficult to enforce a curfew, or time frame in which a guest cannot come and go. Given that you are in a very lively area, known for its nightlife and entertainment, you are probably going to face an uphill battle if you issue a curfew.
-I know a lot of people skim over listings or flat just don't read things, but there are a few steps you can take to better your chances of guest reading and understanding the rules, thus following them during their stay. When communicating with your guest before their check in, you can politely ask them to read the home rules or ask them to confirm they already did. Some host also highlight the rules in their welcome messages. Guests are more likely to read these messages as they often contain information for check in.
-Vet your guest. You can turn off instant book so that every guest has to submit a request. This allows the opportunity to communicate with them before accepting the booking. You also have the opportunity to review their profile and look for any negatives or potential issues. If you choose to allow IB, you can set requirements, such as having to have reviews. this helps weed out problematic guest.
I've been hosting and co-hosting for years, and honestly, the bad ones have been few and far between. For the most part I really enjoy hosting and have met some amazing people along the way. However, very frustrating when you get a problematic guest so I can sympathize. Hopefully moving forward everything runs smoothly for you.