New Roommate Threatens To Charge For House Guests Landlord Approved Off

Located in California

My friend [R1] and I have rented a house together for 7 months. We brought on a 3rd roommate [R2] 3 months ago. R1 and I have 5 months left on our year lease. R2 has a separate year lease.

You can see in my post history, but R2 has argued every utility bill that has come up. The utilities are all in my name.

At this point, they are threatening to charge me and R1 for everyhouse guest we have over. Our lease states we are allowed temporary house guests and may have guests stay longer than 14 days with approval from our landlord. Without approval, they are considered a tenant per our lease. I submitted a request for a family member to stay for 2.5 weeks. I also submitted a request for a party. Our landlord approved both requests in writing. We have thrown one party previously prior to R2 moving in.

R2 is threatening charge us per guest per day and is planning on deducting from the utilities.

What are my tenant rights and legal options here? I've never dealt with a roommate like this and I'm trying to work with the landlord on this.