Technology and social changes are the most determining factors for respondents. 91% believe that technology will change the way we use real estate assets.Cars without driver and incremental use of car sharing, will free the space in the cities, with less space necessary for car parks.The Internet will definitely modify the real estate business, both in retail and residential.The 3-D printers will provoke that it will not be necessary to store products, nor even to move them, since they can be generated at the desired time and place.The analysis of data allows a better understanding of the behavior of potential customers, as well as measuring the experience in the process and the satisfaction of those who are already customers.

I was wondering how I would go about establishing these types of minimum criteria and what should I consider for either modifying or using this for my local market?

The loan was modified several years ago and their rates are much better and affordable for them now but roughly 50% of the mortgage is still owed.

Although they're the experts, you can always re-read and modify their work as needed. 

If able to find someone else to take over their note and possibly modify it then there would be no need for short sale.make sense?

I would suggest modifying your loan numbers in Year 2-30 and that will help the numbers be more acurate.  

If I own the first, I can modify the payment terms however I like, and don't need to get the seconds approval.

However, if you've got cash buyers and they are flexible you could modify your sale contract to be contingent on the purchase of your new property.  

All parties have to agree to modify a contract 

Then modify your plan.