And if you make it a quid pro quo, don't you run the risk of violating the OTA's policy of paying to alter reviews? 

The key is ensuring the after-repair value (ARV) supports refinancing to pay off the initial funding without overextending.Fix-and-flip - This requires sharp numbers and market knowledge.

Additonally house tenants take care of lawn maintenance and snow removal, and pay all utilitites. 

You will pay them and everything will then fall apart.

What do you mean you are paying $400 additional dollars more than what you are paying now?

Also, how does one assess whether or not one can turn a profit after paying principal/interest, insurance, and taxes each month?

It pays to have a look at the EMA floodmap and see where you are in regards to potential flooding. 

I walked to the house and met a man who says he was cleaning out due to the loss of their mother in some few weeks back.The guy told me she is  left with 12 years mortgage on the property to pay the bank.

With the HELOC and then converting it to a term loan you will probably be paying higher interest and/or shorter amortization period on conversion which will mean higher monthly payments.

Haven't been there, but pay attention to the foundation - if the floors are level there no action needed.