We'd prefer to have a separate dwelling area but those tend to be few and far between.

Depending on how the property is zoned, you may need a variance, rezoning, or to formally subdivide the lot to make it legal for another dwelling.

Quote from @Garrett Creswell: Arizona cities like Phoenix, Tempe, and Tucson have loosened zoning restrictions to allow more homeowners to legally build ADUs (Accessory Dwelling Units) or casitas (often used interchangeably).Phoenix passed a policy in early 2024 allowing ADUs on most single-family lots, aiming to boost affordable housing and multigenerational living options.Requirements were simplified: smaller lot size minimums, reduced parking requirements, and less red tape for permits.With the new law passing, builders and developers saw a new market open up:They’re targeting homeowners who want to create rental income (especially with the Phoenix rental market staying strong).

I may have to get a variance for the existing dwelling unit's parking requirement, but I believe I meet all the SB-9 requirements.

That's specifically for areas where small multifamily property inventory is thin.As for the homes with multiple dwellings/ADU's...

So to clarify- American Modern -Dwelling with liability (1M)- 1,975.00.   

Basements that are the same foot print to be able to add a second dwelling for more income in the future, and being close enough to the 20 & 285 for commuting.

What is the fastest, cheapest way to eliminate cannabis smell from a dwelling?

I have not had much success as the town does not want it to be zoned as a triplex (even though there is a huge shortage of rentals, it is walkable/right next to an MBTA commuter station, and Massachusetts is now allowing home owners to renovate single family homes into having "accessory dwelling units" but apparently does not apply to duplex to triplex conversions.) 

The local lender we tried to secure a HELOC with said they could not lend on a property with two dwellings on it.