Would the investor have to use an assignment contract between him and new end buyer to collect the mark-up fee aka assignment fee at closing?

I currently live in Tennessee and I have a possible opportunity to in move to the state of New York for a two-year work-related contract come the summertime.

Used PSI last year, they did a bad job, the snow wasn't even bad last year and with several attempts asking them to do better within the terms of the contract, they still sucked. 

I have the contract to use them sitting in my email now so I saw a preview of all the data and it's pretty incredible.

I likely purchased this property too quickly as it was the 4th property we toured and we didn't negotiate on asking price as the house was previously under contract and my agent advised against lowering.

Fortunately, I just call the bank and tell the address of the property I am under contract on, and when I want to close. 

Are you locked in on the contracts with the current set of tenants?

We found two contractors and the bid we received to finish the work were higher than the bid we contracted to complete the entire rehab! 

It's part of their contract to get paid and not getting paid is a violation of the contract.

Our first accepted offer was a 320 unit deal that we contracted, put up non-refundable (yeah, I know) earnest money, and thought we had our financing and money in place to do the deal.  2 weeks before closing a major (several million) partner pulled out leaving us short of the funds needed to close.