If contractor refuses to repair I figured my next step is I will get an estimate from contractors to do proper repairs and send this information along with before and after photos of property and a letter explaining the situation to the current owner requesting for them to contact me by a certain date to get the repairs done. 

You'll have to call around to get estimates but I have purchased preventative treatment for less than $1,000.Do you have a problem with pests?

Is there a place that i can setup estimated value in search preferences (filters) ?

There's a lot to learn before actually learning what you asked, but if you don't know how to estimate repairs or how to calculate the ARV, you won't make it as a wholesaler.

It's been a great equity play (estimate appreciation at 70%) but from a cash flow perspective I am only about $75 net positive each month. 

Attached is an estimate from a local general contractor and I'm just curious how this sizes up compared to other estimates you've all seen - and if we'd be better off managing the project on our own and sub contracting specific parts out.

You haven't even included an estimated costs for the refi...Are you trying to convince us? 

It's also hard to estimate how much cash you will actually be coming up with.

Would you say that Zillow's estimation is reliable ?

The estimate of what I could rent my house for is about $1600.