@Saif Ali We always use Patten Law Firm, with great results.

My approach is......what does my offer price need to be for it to match my numbers and make sense?

As the seller, you can support the buyer in this effort by sharing the competitive market analysis that you received from your agent or by giving her the results of an independent appraisal, if you have one.

The environmental variation is matched by very few places (ocean/Beach, mountains, desert). 

Just hone in on the area around the property of interest, and adjust the filters to only show sold properties in the last 3, then 6, then maybe 12 months if those more recent time frames don't yield many results.

It's 1 door for the entire property, so if the unit is vacant, then I don't have cashflow to pay for the expenses (mortgage, etc), and as a result, i need to make sure i have more money in reserves to do so. 

Depending on your preference, either one will get you the same result.

As a result my credit score is in the 400's.

.* In the end, the #'s pencil, but capital available for rehab will likely result in slower progress toward until rehab completion.And now the question(s)...1) Does it make sense to refinance at some notional midpoint in the rehab? 

One of the downsides is that I have to usually wait a year before the 401k is matched at most of these companies.