Hello,What do you guys/gals do when you get an application with co-applicants that are unmarried. 

Explaining this upfront generally eliminates the high maintenance applicants.

I am wondering what other landlords do for application fees when screening tenants.

How do you recommend I proceed (assuming none of the applicants qualify alone), with one cosigner for the unit or one cosigner per applicant?

lol  that's probably what happened to your applicant too!    

There is currently no fridge, a rolling (not plumbed) dishwasher that sits next to the stove and limited cabinets/counter space. 

7.If you like the property, are you willing to fill out an application for a credit, criminal, and eviction history report?

Zillow's program is cheaper (good for the tenant) and integrates with the rest of their new rental application and rental payment software.

Here’s information about an interesting one:“The Dutch city of Eindhoven is to be the first in the world to have habitable homes made by a 3D printer, in an innovation its backers believe will revolutionise the construction industry.Of the first five new houses to be put on the rental market next year, the smallest, with two bedrooms, has already attracted applications from 20 interested families just a week after images were made available.Known as Project Milestone, the development is said by the Dutch construction company Van Wijnen to offer...”https://www.theguardian.com/artanddesign/2018/jun/...

It's difficult to find properties close to Boston that meet the FHA limits.