For what it's worth, I found this on the HCD site under Accessory Dwelling Unit Technical Assistance memo dated Jan 10, 2020.

I've had pretty good success the last couple years with a combination of house hacking and building Accessory Dwelling Units.

You will start with the larger pieces and fill in with accessories, wall art, rugs, and decor.Because I own cabins in a mountain environment, I try to avoid the new case goods.

Was at one last week that included City of Calgary who did a presentation on legalizing illegal suites and accessory suites in general

Also, if you're having trouble finding inventory in your market, look for single family homes with accessory units or even mother daughter setups.

Looking for suggestions on any specific building materials, fixtures, accessories, furniture, and tech for a STR.  

But then spend a day in craft and antique shops nearby and buy colorful artwork, accessories, throws etc. to give the space a local vibe.

For instance, properties with an accessory dwelling unit (ADU) on the lot that can be implemented as a long-term or short-term rental can perform exceptionally well.

If my property is a duplex, I'm assuming I can add the 3rd unit as an Accessory Dwelling?  

Here's some input to help guide the decision between selling or renting the property, considering the specifics of the property and the potential additions like the ADU (Accessory Dwelling Unit):1.