@jamesTo expand on what @Linda Weygant said about the home office deduction no longer being an audit flag, the IRS now allows a "simplified" method where you simply multiply the square footage of the office by $5 and that's your deduction.One has to think that if the IRS is offering and encouraging a simplified method of reporting, it's not going to be the cause of an audit.

You have the video footage form day 1 indicating that there weren't any significant mark ups, dents, etc. in the walls.  

Looks like you did a good job with new finishes.Just a quick cursory look at recent sales in the area shows that you're an oddball in terms of sq footage and # of bedrooms.

Zillow may or may not be aware that a listing has expired, property has sold, etc.The "Zestimate" is their software's best guess based on available data for recent sales, current listings, etc. for properties of similar square footage and/or configuration.

It takes into account square footage and the number of tenants in the unit.

We decided to close in the porch to add some sq footage and convert to 3/1 as well as convert the jack and jill bathroom to give it direct access to the common area.  

My basic understanding is that you charge the tenants each month based on the ratio of their unit's square footage to the total square footage of the property.I would give credit to the BP member who I saw this from but I can't remember.For an easy example, consider a tirplex with identically sized units.

Get a copy of the property maintenance code used in your area and make sure the square footage will work for bedrooms, living space and dining space and that there are enough windows and doors the proper size and location for egress, etc.  

I wouldn't get caught up too much on square footage.

I know there are some commercial insurance providers that are more geared towards large multi-family projects and have a base charge on total square footage and then a "per unit" additional charge . . . at what point does this become the right approach for SFR portfolios?