My biggest lesson learned is that I need to make sure I do more research before buying any properties to ensure they can cash flow and are in the best possible area.Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

My biggest tip is to respond to EVERY inquiry even if they have a lower budget than you want. 

Generally speaking, in most markets, your biggest wholesalers have the ability to be buyers as well so google whos the bigger buyers in your area.....

Could you explain more about the benefits and downsides of classifying our property as a duplex versus a single-family home with an ADU?

And that's the biggest part to this dilemma.

The only downside is it takes roughly 5 days from the tenant withdrawal until it hits my bank account.

The downside I am trying to find a way around is how to insure correctly without the bank getting notified of the change in owner. 

Military and am currently working at the worlds biggest surface coal mine.

My biggest concern now is I am a bit lost on what markets to begin looking into.

There’s only possible downside, zero upside.