I've called the attorney general and the city housing authority.

If a seller refinanced a house at around 220k and has about 120k left in mortgage, but the house also appreciated to 450k, how do I structure a subto/seller finance deal?

They bought their house near Lucca, Italy.  

I only have 1 property under my belt and am currently house hacking my SFH.

These special assessment were thousands of dollars, and there was no sufficient reserves from the monthly fees to cover these large biggers, so the owner were required to cover the shortfalls out of pocket, what a great way to ruin your cash flow and ROI.There are benifits to condos, including tennis courts, playground, swimming pools, club houses, and fitness facilities. 

Possibly break loan covenants and can't cure default, lender takes back property.  

I still have one house with some existing K&T.

If the house is older than 15 years old and an ADU is added, it can become rent controlled.

I have a lake house near a University.

Another option is moving out of your place and doing a house hack.