Purchase options when owner wants payment delayed to accommodate 1031

I have an opportunity to purchase 2-3 SFRs but the owner has not located a suitable property to utilize 1031.  My goal is to take ownership of these 3, do updates and get them rented. I'd like to get some options/techniques from BP folks but also would like to hear about potential problems with such unorthodox arrangements.

First thought is to delay total payment while providing minimal monthly payments. Timing is important of course but I could include a 60 day notice to get property financed.

Thoughts?