If you have a good FICO, a decent down payment and closing costs, go ahead an do the first one. 

I had specifically asked for numbers including mortgage payments and they emailed to me.

A lot of them contain Balloon Payment Provisions. 

Because for a certain type renter it’s just SO easy to continue renting fully furnished rather than having to spend $20-40k on furniture; come up with a down payment on a house purchase; and or worry about repairs and maintenance.  

Meaning if the borrower stops making their payments the investor can lose all of their investment.

.❌ Emotional Stress – Handling tenant issues (especially late payments or evictions) can be stressful, especially if you live in the same building.Hiring a Property Manager in ChicagoPros of Hiring a Property Manager✅ Less Stress & Time Commitment – A property manager handles everything from finding tenants to collecting rent and coordinating repairs.

I'm considering leasing out storage space for boats and RVs.  

You only need a place to track tenant information, payment history, maintenance, etc.

I have equity in my CO rental; I don’t have a large enough sum saved up for a down payment yet so I’m wondering if a HELOC would be an option on my CO property. 

I assumed you'd use HELOC for down payment + another loan for the rest. that is 100% financed.