Hello Bigger Pockets People!

My name is Moise Julien and i am I have been keeping up with BP since last year while i was injured and out of work. I would like to get to first first deal this year and i am in need of some assistance. 

I am interested in purchasing a Four-Plex multi family property. I found one, i need to find some comps to make decided whether it is a good deal or not, and i did some ESTIMATED calculations for ROI because all information were not available, but ultimately, I am unsure of my work. I would like to have this property as a Owner occupied property.

In order to make sure that my calculations are concrete, What are some questions would y'all recommend that i ask the seller of the property? I was thinking about the current Rent of the Tenants, List of all Landlord Expanses such as Property Taxes, Property Insurance ect... 

Is there anything else you fine people that can recommend that i should be asking, or is there perhaps a guideline i can use to make this process a whole lot easier? Any help or recommendation through this process would be greatly appreciated.

I thank you all for the opportunity to post and receive some guidance as i look forward to this journey!

Looking forward to hear form you all!