This can lead to all kinds of problems including potential legal issues.

If this is the case, is there some reasonable rules of thumb to use here (e.g. how much should I be holding out for and what kind of a range in mortgage rates should I expect?)

@Jay Chopra  could you please clarify what you mean by 'Gap funding partner' and share what kind of terms come with the refi exit strategy?   

If you can't get comfortable doing that kind of leverage than don't.

These kinds of thieves take more than money, they erode our ability to trust and make us question ourselves.  

My agent, also an investor with say around 100 doors, expressed skepticism that sellers will be willing or able to break out these kind of details when selling a small segment of their portfolio, and cited the expenses of a CPA keeping track of 100 LLC's as a deterrent to keeping properties separate.I had assumed that it is a relatively easy matter to keep transactions for separate properties separate.

Would you be so kind to let me know of a few companies the turnkey containers.

You will have all kinds of people looking for your deals.

Heck, ask who would want to be on a buyers list for this kind of deal and I think you’d find takers if you want to be doing that much rehabbing and your staff/contractors can keep up. 

Start out the relationship on a good note with this one kind gesture.