If the note has truly been administered between private parties the borrower will want to provide copies of the cancelled checks and a letter from the original note holder with a payment summary.

You step in and offer them a creative finance solution that looks like this: (these are real numbers btw):Seller asking: $275,000 for 3/2 Single family split level, 1400 Sqft, with bonus room in basementYour Seller Finance terms as follows:Down payment: $20,000 cashSeller carry back financing amount: $255,000Terms: 5 or 7 year note with balloon @ 2.75% (or any negotiated terms here)Principal & interest: $867.61 per month (wow!) 

Then once you have your golden ticket (pre approval letter) from the lender then you can begin looking for homes with a realtor and go shopping.

If so, ask your lender if an letter from your employer stating you work remotely would suffice the deal. 

Do we need to cover ourselves, and contact the housing authority via certified letter or email so this doesn't come back to bite us?   

. - Love letter.

Read the lease to find out how much notice you need to give that you are moving out at the end of the lease and give them written notice (ie send a letter or email and ask them to confirm they have received it). 

If you make this a balloon payment in say 5 years, you've helped your cashflow, and you can refinance to pay out the balance of the 2nd mtg.I do have to ask though - you seem quite emotionally invested at this point - what are average house prices in this neighbourhood?

The lender will give you a generic preapproval letter that states how much they are willing to loan you when you do decide on a property. 

In addition, the owner of the home must not own more than three single-family homes.3) They are unable to provide sufficient documentation, such as the emotional support animal letter, that verifies the ESA is necessary for their health and well-being.4) The tenant provides fraudulent documentation attesting to their need for an emotional support animal (usually a fake emotional support animal letter).5) The landlord can demonstrate that making accommodations for an ESA would impose undue financial burden or logistical burden. 6) The animal is destructive to the property or displays threatening behaviors that could put other tenants or yourself at risk.7) The size or nature of the animal makes it impossible to house safely or humanely.