Steve, I'm going to find out your secrets here on how to locate these threads and post them! Very good.
The letter and strategy was fine Nick posted, IMO.
As to Bryan's post, I think he meant, return receipt requested, not read, you'll never know if it was read and that's not important.
As to when is the sub-2 appropriate, that is an issue. Likely a sub-2 is not going to be very successful after a notice of demand has been made to your seller. Your sub-2 deal has no bearing on the lenders ability to foreclose. Generally, a borrower can not encumber collateral (which is what a contract would do) after a notice of demand and intent to foreclose has been given. You sub-2 has no effect on the lender's right to foreclose. It's just another notice.
I'm speaking here of loans that are in compliance, not in default and where the seller is agreeable to selling in this manner.
A lender, I will bet money, you will not get a letter saying your deal is OK. But it's not required.
I did receive a letter saying that the transaction I had described was acknowledged but that the bank was not waiving any rights provided under their security agreement. All they acknowledged was that they were aware of the transaction and agreed to contact me in the event it became necessary. Since my disclosure provided an authorization for the bank to disclose loan information to me and allow me to make deposits to the seller's account/loan. I had tons of phone calls, but just one letter as I recall.
The only time I would advise doing a sub-2 (and no reason to use this startegy as other would be easier) would be after a notice of default has been made. In such a case, you don't really have time to sit back and make payments on a defaulted loan. Don't know why someone would think of using a sub-2 in a default situation.
If your strategy is to buy and hold for some time, more than say 90 days, give notice and disclose.
One other comment, as pointed out in the thread shown by Steve. Insurance. The seller and the buyer can be co-insureds, just like a husband and wife, but you don't have to be married to be a co-insured. Banks generally catch installment deals and wraps by the insured being changed on policies. A letter with your new binder can explain the change as pointed out. Many times, I allowed the tax receipts to be mailed to the seller, unless it was a loan servicer, since the seller needs to know that taxes were paid. The buyer can get a copy from the county or the seller, you can leave that issue alone in that respect. Good luck, Bill