Aside from the general questions above, if anyone has more specific knowledge around the keys, specifically Marathon and the advantages of having a stilted home vs concrete build vs modular vs ground level, how that effects insurance rates, financing etc would be greatly appreciated. 

Cash is great, as you have a competitive advantage with a cash offer and don't incur additional closing costs.

Other than having cash on hand and absent a pre-approval from a lender for a specific deal, how does an investor take quick advantage of a purchase opportunity?

That is my advise to you.You need to take advantage of the fact that NO ONE is using intelligence in our space.

If you are a seasoned investor and are buying low priced properties it may work here and there, but to assume that it will automatically give you a competitive advantage is a litte naive and stems probably for superficial understanding of how it works. 

I'm providing a service by getting them the amount they wanted too or close too it, while fully disclosing what they will actually be netting, which is an advantage over even some agents explaining exactly what they net break down will be after fee distribution, transfer tax, title fees, loan pay off etc.) 4.)

This is advantageous from a tax-savings perspective, lack of confusion perspective and also allows underperforming properties to be kept above board by those that are doing well (this last point can be a blessing and a curse all at once, but for the sake of this answer we'll say it's a plus!). 

I've even waived my commission to make my offer more appealing to a homeowner - a good advantage to have in a seller's market.

The most common concern i was trying to address is taking advantage of an unsophisticated borrower and obtaining their property with equity in it, without adequate consideration.

Your contractor is the life-blood of your business so make sure you choose one that embodies all of the above.If you are just flipping a home I do not think you will need an architect but that depends on the project.Good luck!