As a Broker myself in California I woulld say hands down a 7 day listing for an exchange of a buyer is in your favor.  

:This is where the contract between (or at least having something in writing) would come in your favor.

Some lenders will base off the "mix" of commercial vs residential by sqft and some will base off of rent, and some will base off of the unit counts, so you'd want to take advantage of the lender/broker that can fit your scenario in the most favorable way possible.Is the property fully occupied?

Mostly favoring the tenants.

Will court still proceed and grant eviction case in my favor?

Anything and everything can be used as a weapon as long as you know how to used it in your favor. 

Do the numbers change much in your favor in the long run if you're able to have the top and the bottom units rented on AirBNB separately?

If you mean, can you get in good with some gov't program that favor you in acquiring and fixing up run down housing and make it affordable living for people in the community? 

I am concerned about the implications of transferring the property into an LLC, especially since I have a favorable mortgage rate that I would prefer not to jeopardize.Would it be advisable to establish an LLC, obtain a PO Box, and open a business account without transferring my current property to the LLC?

They will also spot any terms that may not be favorable to you and can assist with negotiating the deal.Due diligence is key in any real estate transaction, but especially in off-market deals.