I recently attended Note Expo 2022 this past weekend. 

the marketing must be different than a $400,000 home- What aspects of real estate do the multi million dollar buyer look for, As opposed to a couple hundred thousand dollar home? 

I think there is definitely a couple strategies at play here for you and your family. 

A couple of treatments worked for me.

Do you need all this for a couple of rentals?

When someone else is on ownership (or deed/title) then they would need to sign a couple of things at closing to give permission for a lien to be applied to the property they own - but that doesn't mean that HAVE to be on the loan. 

You should call a couple local banks to discuss the types of investments you may be looking for.Alternatively, a great strategy for someone just starting out is House Hacking.

Initially, I was using Quickbooks (QB) and then when I go a couple more properties and multiple LLCs it was difficult to manage on QB and required multiple QB subscriptions and this got expensive.

It looks like you're on the right track with your math, but a couple things could help.

Now, some of these answers will depend on what state that property is in, how much equity you have, and a couple of other factors...but you can certainly seek out other lenders about a Line of Credit on an investment property.