That being said, besides, looking at actual rental comps that you can get from an agent I also look on Zillow and try to find apartments that are very similar to what I have available.

This would qualify even if the portion used for investment is a part of the main living space, because even though it's being used for investment it still qualifies as your primary residence.

Maybe they can rent an apartment in the district?

It usually starts with a notice being posted, so get that done asap to 'start the clock'.Keep in mind you should receive their security deposit as a transfer from the previous landlord as a part of closing, so that will at least compensate you somewhat for the lost income if they haven't trashed the place and such.One other set of questions would be - do you want them to leave?  

When a vacancy comes up in a good apartment on SFO, operators often have literally hundreds of extremely well qualified applicants at incredible rates.

Hope this helps... can't tell you how many times I had to save DSCR loans that fell apart some where else. 

Currently they are raising capital for Houston apartment complex.

Apartments are good, but they are going to be more transient.

Last year I bought a 4 unit, 2 story purpose built apartment.

Have you contacted apartments personally or are you taking the brokers word?