Understand that from a legal stand point, the law requires an RMLO to originate certain loans, that doesn't mean that RMLO has any expertise beyond origination functions of residential, secondary market loans, they may have expertise, most likely not, especially in non-conforming lending areas.

Conforming bedrooms and bathrooms add to appraised value also.

In those case the seller takes on a huge liability to conform to collection practices, might  have an attorney actually do real collection requirements.

Certainly no matter if your unit is "non-conforming", illegal, or whatever, you bet your *** you better have it be safe!!!!!

Yet the realtor conducted a regular sale of the property, and the buyer received a conforming mortgage. 

Not only will you not be able to count the rent....but if the 2 separate units do not have interior access to one another, you will need to create that access for it to conform loan requirements. 

I have a few off the top of my headNon-conforming zoned properties, way too hard to get around these (sometimes)High crime rates, D class neighborhoods - beware of bad neighbors tooLong list of building inspector code violations being transferred at closingToo many liens on the property (mechanics, tax, credit - you find these in the title search)Clouds on title (relatives in other states that have different plans for the property)Too much "spaghetti" on the table (hair on the deal, I am Italian and like food references)Happy to share my "Due Diligence Checklist" from our BiggerPockets Blog.

If it's not affixed and/or there's lot rent, chances are it cannot be financed (at least by conforming loan guidelines, maybe a niche lender will lend on it) and it'll narrow down your buyer pool or price. 

Because her FICO score was < 680, she had to get an FHA loan, with its attendant mandatory mortgage insurance, rather than a conforming loan, even though she would ideally have put 20% down to avoid mortgage insurance.

With 1-4 family conforming loans, the net impact of the property based on the fannie/freddie calculation will be looked at as an increase to income or an increase in expenses on his DTI.