But I also sent 6000 letters to find out what's up with off-market-magic and what I found is that they work mostly in areas where poverty and financial literacy is an issue.

Most are only seller financed for 2-5 years with a balloon payment.

We're hoping to do seller financing when we buy our first rental investment property, so I'll be hand-writing letters to long-time owners of rental properties (mostly single family or small multi-family).

And yes, absolutely, we are very much “company policy” driven, and will uphold the lease to the letter   I found that works best to off set arguing from tenants.  

. - zero tolerance for late) and enforce them to the letter. 

I just gave him a letter increasing his rent and I asked him to sign the acknowledgment of receipt and he outright refused.  

Discuss the issue with the tenants before sending them a letter. #3 Depends on their reaction in the discussion.

Essentially I want to know if the deal can be killed at my discretion as soon as lender A denies financing or if I would then have to get denial letters from lenders B and C as well to kill the deal.

DSCR only requires that the rents be equal to or greater than the PITI payment or the ITI payment if you go I/O interest only.You can use DSCR for a cash out refinance, Purchase and even a "Rate and term" which is when you want a lower rate or get out of a HML - Hard Money Loan, Balloon payment, Adjustable rate getting ready to expire/adjust (Recast).

Quote from @Eryn Garcia: Quote from @Theresa Harris: If you use the search function, there are a number of threads on this.Pros-you can rent by the room and make more moneyCons-students are often less experienced at living on their own and may do things that result in repairs (eg wrong soap in dishwasher), higher turnover, more calls to deal with things, higher chance of parties.If you do it, you may want to get a cleaner in once a week to clean common areas (students clean their own rooms and keep the place tidy, wash their own dishes) and you will need to get someone in to take care of the yard.Thank you so much for sharing could you tell me where the search function is  Up that the top right is a magnifying glass (a circle with a handle on the bottom right-could also look like the letter "Q") to the left of the bell.