If we're going to just talk in hypotheticals, of course anything is probably possible anywhere but highly unlikely. 

Quote from @Breland Clark: I would like to know more about developing land and subdivisions for new builds and apartment buildings. talk to the land development arms in your city or state.

As for rent, the three parties agree on a fair rent for the apartment and that is what you pay the partnership every month in rent.

Glad to be a part of this community. 

Is this normal cost or high?

These are becoming very affordable from retailers like Home Depot and Floor and Decor, and they really set you apart from builder-grade homes!

, it's still highly unlikely that an appraiser would have given value to this bathroom in any case, so we're not losing anything from an appraised value standpoint.Seller should be more than OK with it once you educate them on the fact that of all the offers they are evaluating, yours is the only one willing and able to execute a plan to close on-time, without delay, in spite of the flagrantly illegal and unpermitted bathroom.

Please, please, PLEASE learn how to underwrite an apartment before taking the next step.

There is one upstairs apartment that can be turned into a str. 

Would real estate prices in certain regions rise rapidly due to demand from both local and international buyers?