@Kayla Weigel I will try to help you a bit, I'll send you a DM on BP hopefully you can leave us a review. Also, it goes without saying that you should consult an attorney; Okay briefly reading over your lease agreement, it's a good agreement but it is very loosely written and does not provide for many remedies prior to eviction so... that is something you should look to improve on moving forward, there should be an escalation of force in as $XX fee until rectafied and THEN otherwise eviction, also you should number your lease clauses.
Regarding the current situation first and formost, I understand you live in the property as well but you should certainly take on a 'HANDS OFF' approach in regards to internal disputes amongst Tenants; you are after all a landlord, not the ethics police nor the real police.... if other Tenants have issues such as those they should inform you and then they should contact the police... if it's not police worthy than it is more than likely just internal bickering.
Okay, now reading over your lease agreement as I noted earlier and as you mentioned, it could be better but, there is one clause 'Noise/Waste' that could apply here, is the Tenant creating a nuiscance? possibly... but to proceed with this you must get everything in writing... meaning that when other Tenants complain to you, you need to have them do so in writing (email is fine; not text) otherwise you should inform them that you won't be able to assist. IN ADDITION once you do have the complaints in writing, section 'Disputes' in your agreement REQUIRES you to attempt to find a solution with the problem Tenant before escalating. Again, you should be able to put this into motion as long as you start a paper trail now, if you haven't done so already; you want accounts from different Tenants covering different instances in writing to show a pattern.
I will mention it once more, you are landlord/investor - not the ethics police, nor the bickering police, nor an investigator - aside from property maintenace issues and rent, nothing else is your resposibility nor should you involve yourself in issues other than these.
Moving foward: 1) Enter into month-to-month leases instead of yearly (term) - they are the SAME to YOU but month-to-month give you all the leverage should this occur again in the future. 2) You should add a clause to elaborate on and expand on the current 'Noise/Waste' clause and the new clause should focus mostly on nuiscance and violation of other Tenant's quiet enjoyment and the remedies (fines) leading up to eviction if the issue is not corrected. 3) You should add a clause to protect yourself from the other Tenants (the good Tenants) ensuring to clearly spell out that you are not resposible nor do you guarantee that other Tenants will abide by the lease nor is it your respobility to enforce the lease vs. other Tenants, nor do you guarantee safety. 4) This is the most imporant one that will fix most of your issues: Because you are adding #3, you will now add yet another clause that gives ALL Tenants the right to enforce the lease in regards to your new 'Noise/Waste clause 2' against any other Tenant who violates it and will idemnify you and hold you harmless, ensure to limit the right to only the pertinent clauses ---- essentially, if Tenant A complains to you that Tenant B is making funny faces at them... you can inform and remind Tenant A (in writing) that if the issue is a problem they have the right to pursue legal action vs. Tenant B as per your new clause... the end... you are no longer stuck in the middle nor are you the bad guy (you will however still retain the right to pursue Tenant B via fines or the same, but ONLY IF YOU CHOOSE and can be done so in conjuction with other Tenants)
I hope this helps, I send you DM on BP, I would truly appreciate if you can assist.
