Jeff - all great questions, and there's an abundant amount of information that I think would benefit you. Question #4 is the one most in my wheel house, so I will start there.
The first step on this or any investment property mortgage question is to make sure that you are using a lender with proficiency in investment property finance and the ability to originate mortgages without overlays.
You mentioned "broker", and although your mortgage person may be best in class, you truly need an originator that can go straight off Fannie/Freddie guidelines. A lot of what creeps in as far as no-nos is perpetuated by lenders with overlays. Fannie/Freddie are VERY accommodating, and I have a great track record working with investors.
Rehab-to-perm is a GREAT program, and NW should be able to set you down this path. This mechanism allows you to get in on on investment properties with a much smaller cash position. On a straight mortgage purchase, you are looking at 15% down (but with a higher rate and MI), 20% down for an okay rate and 25% down to get the best rate, really. You can work your way into a 25% down position with 10% down through a rehab-to-perm loan. Again, NW should be able to help you or at least connect you with Sherman Bridge who has good options in that area.
Circling back to mortgages, though, ask your broker friend to detail their expertise in working with investors. I'm not trying to poo-poo on that relationship. After all, lending is a relationship business, but you have subject matter expertise or you don't. I work out of Colleyville, but i have people from as far away as Houston that routinely call me for guidance on structuring, loan options and, of course, origination.
Arm yourself with a team of people that can get you where you want to be. Yes, Fannie and Freddie are the least expensive path to home ownership, but the path from Point A to Point B can not only look very different depending on the specific situation, but it can also make or break your financial success in this endeavor.