Holding company typically if you have multiple companies like a property manager, own property and other businesses. you will end up spending more per year on accounting and state stuff than what you make on your rentals. 

Not sure about CO, but we make tenants sign a NON-Refundable Holding Fee (not Deposit) Agreement for any monies received prior to move-in to HOLD the home for them.

Think from a bank's perspective.A owner-occupied 30 year mortgage is at risk of the borrower losing their income becoming disabled, any number of personal crises.A rental home 30 year mortgage is at risk of the same issues, but you can boot the tenant and find a new one -- thus resolving the issue.I'd argue that rental mortgages are far less risky than conventional mortgages, and the fact is a conventional mortgage is ensured by the federal government "ironclad" so the fact that the pricing is the same when a rental mortgage doesn't have that federal backing really speaks volumes.Let's fund one!

I’m Tieirra , a passionate real estate investor focused on fixing and flipping homes to unlock their full potential and building long-term wealth through buy-and-hold rental properties.

However, if you may experience more appreciation in the home compared to a 4-plex.

I would look at the DSCR loan as the first option.By the way, I suspect you are going to be disappointed by any refi appraisals   ADUs typically appraise poorly   JADUs can lower the property value Vs having the space as part of the primary unit.  

I know we can get 25-30% in single-family homes with a little luck.

It went from a rundown home and outdated in every aspect to an up to date property that I rented for 2 and a half years then sold What was the outcome?

Typically will be rent by rent strategy (which is tough for none owner occupants) or College rental.   

A general home inspection won’t go in depth enough to confirm the actual condition of the line.