If someone wants to film on your property it's not a booking you can do via Airbnb. They need to pay a full commercial rate, you need a clear contract detailing how the property will be used, whether they want to move around furniture, what happens in the event of damage, what they are bringing in in terms of catering/toilets, staffing during the day, how many are staying, they also need to provide you with a copy of their liability insurance.
If they are arguing over the cost of hiring in toilets it sounds like it's not a suitable booking for you. I would say no.
Hilarious they are asking for a discount when they should be paying commercial rate @Doug793
If you want to hire your place out for filming using a film location company who will have proper contracts and commercial rates in place.