So this is common thought and why it is a real challenge to get debt secured by the ADU value add at higher than 50% of the addition cost. 

Do you have to keep the security deposit in a separate account?

Acting like a broker dealer is scarily common.

The information is typically - lease start and end date, how much rent is, what the security deposit is, and how much in advanced rent there is.

I wanted to have a spot to rent out and cover the monthly mortgage payments while securing a small spot to have for myself in the next 30 years for when I no longer reside in Charlotte but want to visit friends, or downsize.

If your have tenants leave every 1-2 years and if it takes you a few months of lost rent to secure the next tenant what does that do to your numbers?

Due to recent security frauds and banks not covering losses adequately, apps like Zelle may not currently be the best option.

I used furnished finder and keycheck to find tenants, screen them, and collect rent/security deposits. 

I do a lot of direct bookings that take security deposits, but with Airbnb, they are always tough.

Like you, I was eager to start investing in real estate but decided to hold off until I had more visa security.