I wouldn't recommend getting a real estate agent license for your own investment activity.I think the main advantage is that you would be able to enter vacant properties without waiting for an agent to show them to you.Most of the training revolves around proper disclosures and equal opportunity.

Take advantage of this if you have the available to you.I also think that if you solve #1 above then your credit card debt will magically disappear.

My question is what is the advantages/disadvantages to putting say 3.5% down vs 20% or 10% I understand putting more down avoids mortgage insurance.

In a perfect world, accepting prepaid or advance rent would be an advantage, but there are many dangers and pitfalls which should be considered before the decision is made to accept prepaid rent.

Not a requirement but take advantage of their knowledge and experience in their pet markets.

The advantage in multifamily, is if you need a new roof, you only have to deal with one roof, one mortgage, one sewer system as opposed to 10 roofs, 10 mortgages and 10 sewers and so forth.

One key advantage I could see in a new neighborhood is simply the free exposure of buyers interested in the new subdivision especially if you can offer better finish or a more appealing design than the competition if it's all fairly cookie-cutter. 

Good deals don't last long and you need to be able to take advantage quickly.  

@John Whitridge Multifamily properties are advantaged by convenience and by a lower net operating cost.

Definitely make advantage of all the resources this site has to offer, the podcasts, blogs, books, forums and so much more.