Also, if you're not skilled at rehab design (interior/exterior design), I HIGHLY recommend you hire a designer.  

I haven’t looked inside of any units of the quadplex but I do know the exterior was remodeled.

I would try to leave exterior, landscaping, and yard work and the final steps. 

The exterior is terrible and needs to be redone, the inside looks bad too with the ceiling and walls falling apart, and I'm guessing the hvac and other systems will need to be replaced.My question is, can somebody give me a ballpark estimate of how much it would cost to rehab this house?

Hi everyone! I looked around to see if this question has already been posted but couldn't find anything.I know a lot of people say that painting brick is a bad idea since you have to re-apply paint every ten years or ...

The exterior walls have rotted through in parts. 

Complete dress up of the exterior; Enlarged the upstairs deck with the monster views.Added a 'Margarita Bar' off the kitchen/family to take in the nightly sunsets.Remodeled two bathrooms, some new wood flooring, new paint throughout.What was the outcome?

You can also expense the portion of mortgage interest, real estate taxes, homeowner's insurance and exterior renovations based on the percentage of the property which is comprised of the rental unit(s).Example 2000 Sq Ft duplex.

The agent proceeded to provide only three pictures of the facility (exterior main entrance, kitchen of one unit, and the backyard) and relayed that I can only perform a walk-through upon the submission of a Letter of Intent.Is it common to supply a LOI prior to seeing the units in an MFH? 

I suggest you read “magnetic capital” book to help your further.