Were you originally planning to just renovate the existing SF home on the property and live in it? 

Meaning you can add another unit to your existing structure and 2 more units on the new subdivided lot.

How to Structure the Deal to Protect Your $20KIf you’re willing to cover the $20K arrears, here’s how to protect yourself:Option 1: Secure Your Funds with a Lien or Escrow AgreementUse an escrow account: Deposit the $20K into escrow with clear terms—if the assumption is denied, the funds return to you.Record a promissory note & lien: If the deal falls through, this would give you a legal claim against the property to recover your funds.Option 2: Sub-To + Wrap While You AssumeSubject-to deal: Take over the existing loan payments before assumption approval, securing control.Escrowed deed transfer: The seller signs the deed into escrow only to be recorded after assumption approval, ensuring they can’t back out.Lease option fallback: If the assumption is denied, consider a lease option agreement until another solution is found.Option 3: Negotiate a Seller Financing HybridAsk the seller to carry a small second note for the $60K equity gap at favorable terms.Use your $20K as a down payment, structured as a secured loan against the property.3.

This amounts to lost opportunity because if you had purchased RE, at the closing it can start producing return. 5) ADUs detract from the existing structure whether this is privacy, a garage, or just yard space. 6) this is related to number 1, but there are many more buyers looking to purchase homes for their family than there are RE investors looking to purchase small unit count properties.

We have everything from a small amount of senior living in an existing condo plat, to average size fee simple and dense build to rent with storage.

Some people simply say 5 stars don’t exist because God is the only perfect thing in this world.

Like you said, preferably convert an existing garage.

The current tenants are month to month and not interested in buying, and the existing mortgage balance is assumable (3.65%) for qualified buyers.I know it's a great house -- and with the assumable mortgage -- a great buy for someone looking to save with current interest rates sitting as they are. 

This process can be uncomfortable at times but can also be rewarding.

. - just the inconvenienced existence of fixing up one project at a time.