Why would one go with you instead of one of the proven pros on here with a few thousand more than 8 posts, with proven track records and a history of helping people and demonstrating their knowledge?  

You must be able to demonstrate that you had the intent to hold your relinquished and your replacement properties for rental, investment, or business use in the event you are audited.IRS Treasury Regulations do not require investment property to be held for any specific period of time for 1031 Exchange purposes.

If that's the case you should be able to demonstrate extreme hardship and inability to pay.You have to remember often times the person you call is the servicing company and not the lender.

Over "selling" a deal, a grey area, demonstrates your knowledge if you're calling a dog in a rougher area a great deal and over estimating the potential.

Length of Self-EmploymentFannie Mae generally requires lenders to obtain a two-year history of the borrower’s priorearnings as a means of demonstrating the likelihood that the income will continue to be received.However, a person who has a shorter history of self-employment — 12 to 24 months — maybe considered, as long as the borrower’s most recent signed federal income tax returns reflectthe receipt of such income as the same (or greater) level in a field that provides the sameproducts or services as the current business or in an occupation in which he or she had similarresponsibilities to those undertaken in connection with the current business.

Loan mod's drag out forever and rarely work.If they can demonstrate financial hardship, a short sale will keep them in the home longest payment-free and not have the default balance chase them.  

Therefore, their preferred way is to demonstrate maximum market exposure by listing with an agent  who uses MLS or offer auction services.As for research and list building, sharp Pro's hire researcher to search court and recorders records to their own specifications. 

But still no statutory holding period only your intent and how you demonstrate that. 

You can still set credit and income requirements, and as long as you can demonstrate that is your policy then you are not in violation if you deny an applicant with a voucher.  

The true answer is - long enough that you have demonstrated your intent to hold for productive investment use.There's two extremes - If you completed your 1031 and moved in immediately you obviously did not buy it with an intent to hold for investment.