Multi-zone mini-splits might be a good option if you are looking to put in a long term, maintenance free (relative to window units in and out each winter/spring) and could conceivable add value, but they aren't cheap. 

The most important thing is to talk about every conceivable situation before hand.

It might not apply as much to properties in the price ranges you are dealing with, but as prices have kept increasing and incomes haven't, it is conceivable that there is a limit to appreciation.

I just can’t conceive of getting involved in the daily operations of running a STR again.

Your lawyer would have you cover every conceivable circumstance with dozens of pages.

So it is conceivable for these "investors" to consider cap rates in valuing the SFRs.So,"Do I look like I don't know what I am talking about if I market a SFR or duplex and mention its cap rate?"

It is conceivable you could see a one dollar US minted coin be worth 5 (or more) of the Federal Reserve notes.

You have access to tens of thousands of forum posts that cover every conceivable strategy in RE investing, its better than a gold mine. 

Going into work and knowing you don't have to work is an amazing feeling.Whatever the mind can conceive and believe it will achieve.  

It is conceivable I could do a short sale and retail the house.