You also have an option of appealing the tax assessment.

. ;) Skip the professional photographers and do it yourself.

In my mind this would encourage an interested buyer to make a quick decision because, as the price becomes more and more appealing, the competition could step in and take away the deal.

will you need to upgrade the duplex to have better appeal?

I did not know it was a model that did well, but I can see it plausible.I would consider buying an ugly home, but would need to investigate it further to see how or if it appeals.

Take photographs and possibly a video before and after the rental.

Part of the appeal is to have a house we can stay at when we are in the area (usually about once a month).Our goal is to buy at least one single family home per year for the next several years, so I'm guessing we will end up doing a combination of long-term and short-term rentals. 

Call around for local lenders even banks and hopefully you find a quote that is appealing.

Maintenance  is not the same a Alteration and the plastic certainly is an alteration and would effect the curb appeal. 

I have primarily focused on flipping to sell because that is what appeals to me the most but I pretty much understand the basics behind other methods as well.