I also got involved with a builder in Florida who has yet to produce the first of three houses they're contracted to build, which was a major hit to my available funds as well, setting me further behind.I also figured if I fell a little behind in saving (18 months instead of 12 months for example), I'd still be making progress.

It would be a direct sale with no brokers involved. 

Although the cleaner is probably the most important piece to the puzzle for your STR success, there is alot more involved with managing it.

Out of state investing involves too many moving parts.

But when applying for a new conventional loan, it still has to be counted. 

If you find a sublet-friendly co-op and it requires an "All-Cash buyer", there could be a good reason.The points you mentioned regarding co-ops are valid but do not apply to all co-op boards across this market.

In the cities the government got involved in housing and low income housing was built for poor people.

My goal is to understand the current demand and rental potential for ADUs in this part of the city, as well as the costs involved in building.

------------------------------------------------------------------------------------------------Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?

There is work involved as you have well found out.