House hacking & General RE Questions

[Lathan Cram]

My goal like many other aspiring RE investors is to get started via house hacking a duplex through FHA. Live in one side for a year and after the year is up rent both sides and roll over profits/savings in to acquiring additional buy and hold multi family rental properties.

As I read all of the articles here on BP I figured I'd take the time to ask a few questions as well. Here are a few questions I have off the top of my head. Would anyone be so kind to provide some clarity on these questions? 

1.) When paying PMI, you pay that on top of what you are paying for home owners insurance? 2 separate insurance costs, correct?

2.) Do you think it is a good idea to purchase a duplex that you can't afford if the other unit is vacant? But when the unit IS occupied it minimizes your expenses. Also Keeping  in mind that the property will cash flow once you move out. 

3.) What is the best way to accurately estimate what you will be able to rent a unit out for?

4.) Is it true that in some areas house hacking a duplex just won't work? If so, in what type of areas is this usually the case? 

I really appreciate any advice. I'm ready to take action and don't want my first deal to be a bad one.