New Member, Previous PT REI moving to FT REI, general advice?

[Nathan Dubes]

Hello my name is Nathan and I am new to the site!  We have a handful (4) of rental properties in the Phoenix area (all condos) and recently decided to make the jump to manage them ourselves and go full-time into real estate investing.  I'm a lifelong engineer, married to an MD (sugar mama) and for family reasons we wanted to have one of us in a career with a bit more day-to-day flexibility as our young child (and hopefully more on the way) grow up.  Added important bonuses of tax benefits (with my wife's salary we really need them) potential earlier retirement, diversification, etc of course.  I have spent a lot of time "stalking" these forums for advice over the past few months and just joined tonight to become more active.  My last day with my current employer is April 22, and I plan to spend the summer educating myself a bit more.  So I have a few questions to start that I am hoping some members can help with. 

1. Right now all of our properties are held by LLC's. Going to full-time, should we set up a separate LLC for "running the business", or should we just continue to use those LLC's and their bank accounts for expenses and spread general expenses around? I am just thinking about things like office supplies, tools for maintenance, etc, would it make any sense to have a separate LLC for general business expenses?
2. We are primarily starting to focus on multi-family properties from here on out, for now looking for something in the ~$1-2M range based on what cash we have available to put down.  Considering that, I thought one of the things I should do first is probably get my real estate license to help save $ on realtor fees, as well as get myself further educated on the real estate business.  Does this make sense?  We have a good friend who is our realtor and has a lot of experience in this area that we will probably use for our first multi-family deal and continue with networking in the future.  
3. We have been looking for a multi-family property for about 6 months now and it seems like "on market" deals in good areas are few and far between and usually an investor comes in with a full cash offer.  Any advice on finding off-market deals?  Phoenix is such a huge market, its hard to know where to start trying to find off-market deals and contacting property owners.  
4. Any other advice for someone moving into this full time? I am joining the local REI club. My biggest fear with this change is just keeping myself busy and avoiding "rookie mistakes". I've been in a structured corporate engineering environment for a long time so this is a little scary!

Thanks for your advice and inputs, this seems like a fantastic forum - looking forward to networking with you all!