A lot of landlords will fill a multi family unit property with less then desirable tenants to deceive potential buyers by showing low vacancy and great cash flow.Maintenance; This is the tricky one.  

I was working for my Uncle at the time who owns a lot of buy and holds and we went to one of his SFRs which recently became vacant and the previous renter left his brother behind (mid 30s but very slow mentally) and he was using pots around the house for bathrooms for at least a month.

I think you can fill out a pre-approval app online, too.

Also, limit the  opportunity where someone can can fill in data in areas like Other Contingencies or Other Considerations.  

I would have them fill out an application, run a credit, background, and if they pass your min qual standards, keep em.

Welcome to Bigger Pockets @Cliff Bailey BP is loaded with all the information you will need to succeed in whatever niche of real estate investing you wish to pursue and the community is filled with knowledgeable investors and professionals to learn from and connect with.

I know all the neighbors and they make small comments about his personal look and casual pot usage (which alone is not terrible as long as he doesn't cause trouble).

What I learned were real estate laws and how to fill out contracts.

Generally, I would do that and have everything except the final price filled in, when I get to the meeting with the owner. 

Sure, it will look great as long as both units are filled.