Tenant keeps threatening civil suit whenever I put any notice on door citing harassment (hiding a dog-no pet deposit).

The problem is that you must have a registered agent in that state in order to domesticate it. 

I require first month's rent and deposit as well as additional pet deposit within 2 business days of approval, if you are unable to do so I move on to the next one. 

CYA....cover your a--You, as the new homeowner and Landlord with an inherited tenant should:Get your hands on the file --- or a copy of ALL the contents within the file --- from the previous LandlordPlace the Security Deposit funds and any Pet Deposit funds in an escrow trust account Conduct an immediate property inspection.

My rental agreement mentioned they were allowed to have only 1 pet and had following clauses that were in clear violation:1.

3 x income, proof of employment and permission to contact employerrecommendation from current landlord and excellent payment history for past 2-3 yearsgood credit history, no evictions or accounts in collectionsno criminal associations or background without approvalpermission to check employment, personal, credit and criminal historypets on a case by case basis (quiet, good neighbors, good habits, not aggressive or aggressive breed)additional pet cost monthly and additional pet depositbonus if move in Dec 15, second month freeincludes cleaning service 2 times a month, no additional cost to renterfirst level floors and bathroom cleaned680 plus utilities, cleaning service includedeach adult over 18 on lease needs approvalmust provide access to cleaning person without delay or inconveniencemust submit payments by ACH debit or by means acceptable to property management companydishwasher allowed with approvalshow proof of renters insurance

. - I filed eviction against one roommate for non payment of rent and other lease violations (failure to clean up after pets.)

Decades ago I started charging hundreds in pet application fees, monthly pet rent, lock change fees, and so many other things related to long term rentals, that only a fraction of the industry has started to implement today.

It would be similar to a domestic issue between married tenant....none of your business.Simply make sure you are prepared to protect your income.

They all share and pay rent as one tenant and have 2 pets.