I'm gathering up lots of big seller financed deals out here in the Bronx and I need an attorney who can review my agreements and do quick arrangements with the seller's attorneys.

Basically, I'm highly interested in y'alls opinion how to best structure and pursue such an arrangement.

Account Closed, a seller financing arrangement with an existing mortgage is generally called a "wraparound" mortgage.  

You can also link calendars on each site so you won't double-book I have my VRBO calendar on Airbnb and vice-versa, and both are synced to a Google calendar so I only have to look one place to see what dates may be open or to arrange cleanings.If you already have a cleaner and handyman, use them and send them dates you need service.

The house is vacant at this time and he said that there is an arrangement with the form a contract with the contractor who then in turn deals with the owner?

By creating a pre-arranged quid pro quo agreement such as you propose, you are creating such an indirect benefit.You can, with a self-directed IRA perform the basic administrative services associated with property management such as signing leases, paying the bills and collecting rents. 

Now that real people, however, have bought and sold homes and arranged financing based on terms, at the very least I want reparations made.  

I try to arrange for multiple showings at the same time. 

If you are going through all this trouble of arranging your business affairs to protect your assets, be conservative, keep organized records, and isolate.  

The current arrangement is not working for you and not working for her.