It is one of the best examples of City Council and local registered community organizations huddling together to create restrictions intended to thwart development but here they are doing it in a manner which will leave new housing stock in the dust relative to other neighborhoods thanks to terrible design restrictions.

Yes, having the court impose a constructive trust on the assets is the remedy for a claim (under these circumstances) for unjust enrichment. 

Many lenders limit their loans to around 80% of the purchase price to mitigate risk, which can indeed restrict your cash flow for renovations.

Hi Kailas - Yes, you can typically rent out the main house and the ADU to separate tenants on separate leases (so long as you're compliant with city regulations/restrictions).

- what do your local laws allow, are there any restrictions

Not seeing many deals in that area, maybe because I am restricted to the <100k range.Yes, I am part of a learning group called Openspaceswomen.

I would like to know if there is a way I can terminate the lease based on the unclear termination date or no termination restrictions indicated? 

I'm up to date on Portugal's various STR restrictions.  

One other thought is fully furnished mid term rentals.. these have worked very good for us in Vegas we get a double or better rent premium on ours.. much less work than STR and you dont have to worry about ordinances or HOA restricting them..

They promise 100% financing, but their lending criteria are incredibly restrictive.