The seller may be willing to Seller-Fi a small portion.

Integrity goes a long way.You can also give a very generous closing gift, offer additional information/services post-closing, and/or offer a rebate for a portion of your commission at/near closing time. 

Clearly at the time the land was divided and sold, it was considered acceptable to building houses on this size lots, even with septic.

Simply let them know of the error and that you'll be returning the "extra" portion now or when they leave (should they need an extra day or so). 

The property was sitting on the market for about 30 days due to the condition, seasonality (it was December), and smaller size of the property (about 1300 sqft). 

Right now all he projects are still being completed, but developments can be 3-7 year cycles depending on the size, so a lot of projects that kicked off in 2020-2022 when interest rates and insurance were below and rents/prices were soaring are still getting completed now.

Would you rather someone have snakes and lizards or a medium sized golden doodle?

LindaMost statutes don’t allow you to collect double rent, the previous tenant would need to be pro-rated back for that portion of time you let the new tenants occupy. 

I’ve done Zillow, filtered it based on Bathroom/bedroom size, home type, etc.I’ve found a few but in the event where houses for rent don’t show up (due to time of posting ?)

By renting out one unit, I covered a significant portion of my mortgage, reducing my monthly housing expenses and easing financial pressure.2.