After a closer look into the disclosures, it turns out that the ADU (permitted, junior ADU) was being rented for supplemental income on Airbnb.

Maybe if it was new construction you could pull plans online from permit but highly unlikely.

Permit me to introduce myself, as this virtually my first time posting on this forum.

Are any permits active on the project? 

Doing it the other way feels like a bad idea…https://www.phila.gov/services/permits-violations-licenses/r...

GC is incompetent, has failed to get proper permits and has stalled on the balance of the work so seller just wants out.

I agree, you can't usually get a permit for anything until you own.

Have you talked to the county permits and zoning office to find out if there is any restrictions on the property?

Most properties that size are 2nd homes and often sell with furniture included, which can reduce start-up costs.No cap on STR permits in Washoe County on the Nevada side. 

The uptick in multi-family construction, with 52 new units being permitted in 2024, underscores a growing preference for apartment living, further supporting upscale conversions or new developments.13210: The sales data shows a 28.5% increase in the price of 5+ bedroom homes, and other categories also saw price increases, such as a 15% increase in 2-bedroom homes, indicating healthy market conditions for larger family-oriented properties.