Scott The Book on Flipping Houses, The Book on Estimating ReHab Costs http://www.biggerpockets.com/flippingbookGood read The Real Estate Agent’s Ultimate Guide to Working with Investorshttp://www.biggerpockets.com/renewsblog/2013/08/24/real-estate-agents-working-with-investors/Download BP’s newest book here some good due diligence in Chapter 10.

Next read J Scott's books on estimating rehabs.

Looking to do first re-hab/flip deal and looking for GC referrals that do high quality work and can respond/provide estimates quickly as deals often get bought up quickly.Thanks

My estimated ARV would have been 100k to 115k.    

Scott The Book on Flipping Houses, The Book on Estimating ReHab Costs http://www.biggerpockets.com/flippingbookDownload BP’s newest book here some good due diligence in Chapter 10.

One of which is a 4 unit.Now, this guy sent me a table with the information about the properties and two rows of the table gave Zillow rent and zillow estimate (for the current sale price of the property).I've already checked all of the local assessment data on the property and all of the estimates are almost double what he has paid for it.

Figure out a rehab cost estimate for the buyer and what specifically will need to be rehabbed and include that in your write up.  

Example: You have a loan against 5 different properties and each property is worth $150,000 the estimated loan is $525,000 or $105,000 per property (70% LTV)Release Pricing:  If you have a loan against 5 different properties and each property is worth $150,000 and you have a loan for $105,000 (70% LTV), you will be required to pay back 1.2 * 105,000 =$126,000 to release the property from the loan. 

Second, your all-in cost is estimated at $113k, but your ARV is $115-125k, So you are taking all the risk of the rehab to get what?

But as a personal investor myself I would say look for someone who has done volume, compare their rent estimate on rentometer, look at comps to compare their price, check them out on Better Business Bureau, ripoffreport.com, turnkey-reviews.com, things like that, ideally tour the places you are considering, but that might be a stretch from Hawaii