Most mold is on the surface and can easily be removed with a bleach solution or one of the many mold treatment products available.

Anything 1-4 units is valued off the sales comp approach, so no, income does not factor in.

It's hard to put an exact amount on it given property values vary so much and there are a bunch of other factors to consider. 

When you factor in the tax deduction you get on the mortgage interest, this 5% rate on a CD closes matches what you would save on interest by paying down the mortgage.

You do have to "kiss a lot of frogs" to find the right tenant, but just factor that in. 

Time was a factor as the bank was set to take the property back and we had pushed the closing back one day before it became REO.

That is another factor to see if it's worth rehabbing the property.

Hi Joseph -  For your first scenario, if you acquire another SFH with a traditional investment loan, the rental income can count toward lowering your DTI, but typically only a portion of it (usually 75% of the rental income is factored in).

This is by far the most important factor in my opinion.

Also, what key factors are influencing your decisions?