Park Under Contract - ? no leases & animals

I have a park under contract in Washington State. Very poor management for last 15 years a lot of upside. No rules have been enforced. Seller does not have leases. Washington state requires annual lease (unless tenant opts to have monthly instead)

My first question is how have others handled buying a park with no leases. In Washington state, you are not able to terminate tenancy and all legal actions require a lease. I’m concerned about not being able to legally proceed if tenants refuse to sign a new lease.

2nd Question: there is 1 tenant who appears to be breeding cats and a 2nd tenant breeding Chihuahuas There are current rules in place against this behavior (however seller does not have signed receipt of these rules) and nothing has been enforced for years. Any suggestions on how to rectify these situations?

Normally you will begin by having esstopal letters from each tenant as a condition of offer.
If you proceed with a purchase upon taking owner ship you send a new lease to all tenants. Your state regulations will cover the possibility of a tenant refusing to sigh, usually the lease becomes effective regardless, allowing you to inforce the lease without a signature.
Once you take ownership you issue new community rules and within a defined period you will begin to inforce all rules. Usually in a situation like yours there will be some tenants you will not offer a lease to and others that will be evicted.
State codes will cover all this in detail.
Once you learn your state codes you can proceed with the purchase/due diligence process.