I am going into this venture with a business partner, he is the boots on the ground guy and is networked with all the right people, and I am providing the capital to get things rolling via a HELOC on my first mortgage. 

@Michael Williams a joint venture partnership would work.

According to Jonas Bordo, CEO & Co-Founder of Dwellsy, "Due to COVID19, renters want more space and control over access to their homes, and this has led to substantial new demand for single family rentals.

I am going into this venture with a business partner, he is the boots on the ground guy and is networked with all the right people, and I am providing the capital to get things rolling via a HELOC on my first mortgage.

Typically folks will get a high interest loan initially because the property is at a discount and wouldn't fit the criteria for a traditional mortgage (fixer upper, cash only).The refi portion is to place a traditional mortgage on there so that you'll have a manageable monthly payment which rent will cover as well as cash in pocket due to the equity that was present.The goal is to control the property with as little money down as possible while positively cash flowing so I'm not sure if get 2 traditional mortgages accomplishes what you're looking for.

Depending on the project you could be a partial owner of a Multifamily Complex controlling 200+ units in the sunbelt with a small investment.

Question 3: Is the longer term solution for the theoretical LLC that I control to own multiple assets, in which case they and their cash flow would be considered by mortgage lenders for future mortgages?

That's usually the best way from the beginning to keep everything under control.

I never intend to evict, but it is the last recourse you have as a housing provider and if the tenants know you won't actually follow through then you will never be in control again. 

I took control of my life and told myself I will only focus on those things which "TRULY" bring me happiness.