What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The approach for a well valued home is to either offer a reasonable amount above asking, or an escalation clause of X amount above the next highest and verifiable written offer up to a maximum price. 

Many agents are lazy and do not take the time to add photos that illustrate unique characteristics, incorrectly add the unit numbers, bedroom count, or fail to verify the square footage that could be greater than the public records the MLS autopopulates. 4, Many MLS properties are listed under the incorrect categories (multi-family under the residential section, multi-family under commercial etc.). 

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

In my opinion, good partnerships always have a "trust but verify" component, and this is no different with Travis & Nader.

Also, your state has the right to audit your LLC to verify you are running it correctly - this happened to one of my colleagues recently.  

Also, if they know what they are doing, they will still verify licensing and insurance for the vendor YOU found!

Some things that might be a concern:1) Obviously have to make sure things are all permitted first2) I don't want the room to "feel" like an addition, so flooring has to be same level/standardized with the rest of the house3) Unlike the rest of the house that has an identically-shaped 2200sqft basement underneath, this added space will not have a basement directly underneath it -- I'm not sure if this poses major cons for some reason that I'm not aware of4) Especially given the lack of basement underneath, I have to make sure that the HVAC can still somehow be piped into this room#2 and #3 are probably my biggest concerns (#1 and #4 I can find out relatively easily)Any tips/thoughts or other experience would be greatly appreciated. 

Verify what the on-line calculators are telling you. 

.- Separate Lease for the Remaining Tenant: If the male tenant wants to stay and can afford the rent on his own, verify his financials.