BiggerPockets experts!

I want to get your thoughts and 2 cents from a philosophical and risk perspective.  I am 42 years old and my wife is 39, we have 2 kids, age 9 and 5. 

GOAL: Insulate my mid-long (5-10 years) term strategy (have income producing real estate to pay for fixed living costs + 5K month cash flow for investing) even during a 2008 housing meltdown.

I know debt can magnify the creation of wealth, but it can also magnify potential destruction.  Investor psychology is unique to each individual, whether they are more aggressive or conservative; I find myself in the moderate-conservative camp throughout my investing career (yes, I have listened to Dave Ramsey since 2000).  I have invested in REITs with my paper assets, but this is the first time I am investing in real property for the purpose of cash flow. Here is my situation, and would love to hear from you as to the risks I need to be aware of that may take me away from my goals. Since this is rental income, I will not lose sleep at night for temporary declines of real estate value.

Real Estate Owned (Assets, income, debt):

1. Tracy, CA Home, value is 400K, rental income is 2100-2400/month range (signing property agreement next month, converting this to rental from prior primary residence); no debt, no mortgage.

2. Birmingham, AL (in contract), Purchase Price 115K (fully rehabbed turnkey), value is 137K, rental income range is Gross 1200/month, 90K mortgage.  This is in a B+ to A neighborhood, 3300 square feet home

3. Birmingham, AL (in contract), purchase price ("all in" rehabbed), 60K, ARV 87K, gross rent 850/month, B neighborhood, Cash buy, no mortgage

4. SOMA Condo, Global City, Philippines Vacation rental (via Airbnb), 2014 average per month 600/month, 150K value, no mortgage

Liabilities:

1. Primary Home in San Jose, B Neighborhood, 700K value, 510K mortgage, 3300/month PITI

2. Lifestyle expenses 3000/month (our enjoyment)

Paper Assets:

1. Investment assets 1.4M (Yearly contribution of 48K)

2. Checking/Liquid Investments: 100K

Income:

1. Earned income (Net, highest tax bracket), $18,000/month (this is also net of  annual monthly investments to my paper assets)

Based on this information, what risks should I be aware of adding real property to my investments? In context of 2008 collapse? Based on my numbers, would you be more conservative? Aggressive? How so?

Thank you for your input!!!

Rollan