The new released estimated total of the effected areas is now in excess of $250 Billion.

I have a little hard time estimating a fair market value given these conditions as I don't know how much to discount the value of the house with these issues presented.

There are also many calculators out there that over estimate the cost assumptions or rent comps.

I will also give them comps / rehab estimates for the property as well. 

If you're looking for rent estimates for MTR, there is a great tool called Pricelabs.

After all expenses accounted for, my Quickbooks is showing an estimated Tax bill of $93K.

Do your underwriting and be conservative in your estimates. 

Land is very tough to estimate value do to it's valie is based on what you can do with it and how much demand there is for what ever is ultimately done with it. 

Question is, if I have the means to put a high enough down payment on a house to be cash flow positive (assuming my expense estimates are accurate, etc.) is that something that I should do?  

What do you estimate is the difference between the market rent (or what other tenants pay) and what she pays?