If the proforma has the rent roll at $1400 a month, there is a discrepancy that could lead you into a bad assumption on your business plan.Also one caveat, be aware of physical delineations around the area like bridges or railroad tracks or a canal. 

Most of the time a newer or unsuccessful agents will host open houses as they build their book of business.

Trusted by 50+ businesses across [region/industry]."

You are starting a business. 

Past performance is no indication of future results.

I think you just have to work it in as the cost of doing business. 

Don't apologize, don't explain how the 'chosen' tenant was more qualified than they were, wish them well in their search.You're running a business and you've made a business decision. 

The best way to grow your business is to help people and give solid advice in the forums.

He had performed virtually no underwriting.  

Having the seller carry a second is not a problem for the first, as long as their business with you is finished and the loan has closed.