Fixed Mortgage does come with closing costs and points upfront which the HELOC does not, except a $95 annual fee. 

For residential multifamily properties (1 - 4 units), can you use a home warranty to take care of the repair costs associated with rentals?

However, I still struggle to understand the art of estimating rehab costs. 

I’m estimating renovation costs at around $150,000.

Real estate is not the stock market and it's called buy & hold and not buy & sell for a reason.I did sell a few properties about 10 years ago when I learned the hard way that going into cheaper neighborhoods was not the right strategy for me, so that was basically a strategy correction and it was necessary, but also costly both in terms of dollars and time.

Sure don't do the renovation, I only do renovations that project a return of 2x the cost of the renovation.

It costs roughly $100/mo but is well worth the expense.  

And that can cost you time and money.

I don’t have any horror stories but every time I go to run a check the cost has gone up.

You are only adding complications and costs with the LLC with no upside  This is all assuming there’s been almost zero appreciation and you shouldn’t sell tax free while you have the chance.