The budget is $400K. 1) HELCO  = all cash purchase with intention to refinance later on2) Refi on another rental  property = all cash purchase3) Conventional mortgageWhich method could save me some money at closing in NY and in the long run? 

@Bridget FitzpatrickCheck out this link https://www.biggerpockets.com/forums/530/topics/818478-determine-how-much-an-str-will-make-using-the-enemy-method

The Comp Sale method and REI in general have enough variables in them already for the average investor; adding in the wrinkle of buying above market value is not something I'd do in general.

The big ones I make sure of are the roof, electrical, mechanicals, foundation, structural.

I contacted the hedge fund to see if they'd be interested in re-structuring terms and holding or selling the note at that point if I purchased the property, but they are really just trying to flip the note and/or property. 

Also, do you have a method to find them?

Looks like a solid structure 

But from further research on how wholesalers do business, I have realized that the house hacking method (FHA 203B, 203k...etc) is not ideal when dealing with a wholesaler.

I use what is the Ackerman bargaining method and it works great.

Structure partnerships that are mutually beneficial.2) As @Brie Schmidt alluded too, you wont be able to scale as fast as you want and you need to take a slower approach.