Finishes, layout (if you can), and anything else relevant to the unit.

In some cases, it just makes more sense due to lower interest rates, better areas, low maintenance, more inventory, and better layout.

The lack of a proper second means of egress will be the biggest problem for both getting approval to have it as a 5th unit and maybe even for insurance purposes (if there was ever a claim filed).Depending on the layout and structure of the building you may want to look into adding larger windows that would allow for escape or another walkout point if possible.

I dont know how the bedroom layout was but lets say it was 4 beds in one unit and 3 in the other..

The bones, size, and layout of the house are excellent, and it is on a nicely fenced piece of land. 

Looking at the layout, it would most likely be a duplex that has one large unit and one smaller unit that have different rents. 

I would think to protect all of your partners you would want to form an LLC and lay out what percentage ownership each partner has.

Generally there is a unit layout, keep on record.

The remodel is a complete gut, with changing the layouts of all the units.

Price, smell, layout, size...something.