Hard money stinks, but sometimes it's the best option and it can absolutely get your foot in the door when starting out.

Plus, increased traffic and noise might be a downside depending on your location.

he suggested to leave it since it is a high traffic area.

Any idea on what would be the per sq foot construction cost for this project?

I can buy the idea that he just started a business & is trying to get a footing. 

One of the major issues with Zillow is that their Zestimates often rely heavily on a price per square foot basis, which can be quite inaccurate.

There are nice restaurants 10 minutes away by foot, and a developing scene.

Any ideas on cost per square foot?  

About 950 a square foot for 1500 ft.² nothing of homes it’s absurd.

Even If there is no requirement for a medicine cabinet I might move it to the side on the left side, And have a mirror cut to fill the entire back wall up to the 7 foot mark if possible for tall people.