But if you are just replacing an existing truss, your contractor may be able to pull a permit and repair/replace an existing structural element as long as you are not altering the original design.You can call for a courtesy meeting/inspection and ask the inspector what it would be required before spending the money with an Architect/Engineer.

Second, for the same amount of money that you would put into a single property, you can be diversified across numerous properties, which reduces your single investment risk.

To my knowledge I believe you can only have a maximum of three current mortgages or three investment properties to your name to qualify for the HELOC program.As @Andrew Postell mentioned definitely ask a few local lenders in your current market and they maybe able to give better guidance.If this 4-plex is your personal residence right now obviously the best thing to do is google "introductory HELOC" in your location and there should be numerous results from credit unions and a few banks that offer a very favorable introductory rate and terms.

A few Key elements in REO's: 1) Place your offer with as few contingencies as possible with as short an escrow as possible.

I know that is a key element in arriving at an appropriate MAO.

We've spoken with numerous sellers, but nothing yet. 

Going through the levels of agent is definitely very hard but if you at min. were able to choose the right agent that represented your side and able to convey your message in a meaningful way I think that could be the defining element here.

But apparently this is common in this neighborhood and each home is identified by a "1/2" as a post script to the numerical address of the home (if that makes sense).

There are numerous reasons investors want to do seller financing and as you've read Brandon's book you've probably learned many of those reasons.One common reason is an investor may not get approved for another loan (depending on how many they have) through a lender. 

Depends on the location of the fire within the structural elements, you can replace just a portion and then braced-it/connect the new portion with steel plates and bolts.