Real estate is not a 1-size fits all thing in terms of "what someone should look for"2.

Unless you have a decent size of down payment greater than 3.5% (Basic FHA down).

Interest only options are typically not available through banks except on very low leverage transactions and smaller banks often encounter size limitations on loans to one borrower.

Whether that be a letter with a different color envelope, or a postcard that is a different color or size.

Additionally, you asked about how PITI would be affected...it's important to know that the "TI" portion of this will not change one bit.  

@Jeff S.A lot of our users use Xero for the accounting portion.  

If you are familiar with your market, you should have a good idea what range your unit should rent within; let's say $300-$1200 is the range of apartment rentals based on area, amenities, size, etc.

A small caveat, I am on site every day for a good portion of the day which helps immensely in the process, if you are hands off it could lead to a longer process.  

A mixed-use property won't qualify for FHA financing unless you can show the lender that you will live in the residential portion and operate your business in the commercial portion.

Here's an example: A free and cleared duplex is owned by two siblings, Bob and Joe, and each own a certain portion of the property.