What to look for when buying a duplex with both units rented

[Abhijit Roy choudhury]

Putting an offer on a duplex where both units are rented out till April 2018. What should I be looking for other than usual. Can I put contingencies like, 

1) need to pass city rental inspection(scheduling that will be tough with in 5 days).

2) Satisfactory review of all tenants related document, lease, income, criminal check, employment, rent payment history

Also any suggestion on what should I be looking for. This is my first multi family. Heavily influenced by podcast 285