I am currently looking for an internship to gain practical experience in managing STRs.

(Search for the Due on Sale clause in a mortgage and you'll see plenty of threads and opinions on that but it is very common practice).I would focus 99% of your time on finding the right area and property, as well as team - agent, Property Manager (@Stephen Glover is a very good start on this one btw), banker, Contractor, etc.

If the dog is doing well, leave it alone.I will recommend you change your practice.

An investor friendly agent can do all sorts of helpful things, like setting you up with a search for properties or connecting you with folks who have recently done deals like the ones you want to do. 6) Consider analyzing a deal or two in your local market, just for practice, with a free use of our Rental Property Calculator (or other calculators).

I have some practice in finding deals but until now I have not had the confidence in myself to execute.

An investor friendly agent can do all sorts of helpful things, like setting you up with a search for properties or connecting you with folks who have recently done deals like the ones you want to do. 6) Consider analyzing a deal or two in your local market, just for practice, with a free use of our Rental Property Calculator (or other calculators).

We mass analyze the entire market here simultaneously and there are dozens of properties that would produce that type of income for less than $700K. 

He runs a best practice group for property managers in Chicago, and he is one of the best-connected guys in the area.

I’ve heard of folks borrowing from their personal network for a down payment, but is this actually used in practice?

They practice in Tax Court.That's not an "accountant. ;-)But frankly, his time is too valuable to argue with you and he isn't going to defend his expertise.