Don't see any major red flags here, so long as you are comfortable in the low income space.

I agree we are quite active in the space. 

I took title to each in a separate series of my LLC, which is the same as per entity protection as having each in a separate LLC but with the organizational and accounting costs of having a single LLC.In the case of each I carried hazard and liability insurance for the INTERIOR of the condo while the HOA carried insurance for the “common” areas, including structural.This particular condo was on the second floor, with retail and office space directly below.  

The hope is the tenant does not move and the older house that had minimal repairs will not fall apart anytime soon.So an old house with minimal repairs to it, questionable areas to invest in, and tenants that tend to live hard in the spaces can be a recipe for disaster. 

A cabin that in theory would have cash flowed positive almost $1K/month had the kitchen drain go through the crawl space and dump out about 4' away from the house.

I too am newer to the BiggerPockets space.

I've wondered about some sort of artists'/musicians' retreat space, but not sure about the numbers of that.I would love to hear your ideas!

Maybe a really nice outdoor space with tv and fireplace?

IDEALLY, we would like to find a property that has or is capable of being converted into a “mother in law”, “ADU”, “Casita”, or any other separate living quarters in which we could rent out the main portion to a tenant (short term or long term) and then use the separate space as our own for when we come and go with business.

The way that things like this are typically handled is that if a lawsuit were to happen, since both people have been behaving under the assumption of a lease (the landlord renting their space and the tenant paying rent), they would probably treat it as if there was a standard month to month lease agreement.