Now I bought this house about 4 months ago as a foreclosure and it had previously been vacant for an extended period.

Peter extended a hand into one local meeting, 2+ to go :-)thanks again

I am wondering - as a bottom line - can an owner of a single family residence rental enjoy significant tax advantages on capital gains when using the residence as Section 8 for an extended period?   

Loan maturity is generally three years, but can be extended up to five years, if necessary, to facilitate the sale of the property.

These are used in significant commercial transactions requiring extend due diligence.

The one problem I seem to be having is decided whether to start out from owner-occupied multi-family (triplex seems to be what I can comfortably afford if I have extended vacancies) or out-of-state investing (with thorough due diligence).

The HARP refinance program has been extended to Dec 31, 2015.

My contract states 45 days to close and the option of extending for around $15 a day.

I recently reviewed some loans where the lender didn't extend properly and created a mess in title, which brought the question for me of how one would do it properly. 

Nope...CapEx (Capital Expenditures) are the large repairs that you need to do every once in a while to keep the property in habitable shape, extend it's useful life and/or increase its value.