Inheriting tenants…. Must do before due diligence period ends…..

[Cash Tomlin]

Hey guys. I am currently purchasing a duplex. Both tenants just signed a lease last month so I will inherit both of them. How do you find out what the current owner did to vet these tenants… ex: references, background check, etc. and obtain a copy? 
What can I ask for legally? Can I conduct my own for each tenant? 

Also, Tenant 2 has a pet lease that does not include a pet deposit or any additional fees for 2 fifty pound dogs. Current owner did not sign the pet lease. Thoughts? We normally charge a refundable pet amt. plus a monthly pet fee for each pet.