Unless you're engaging in super risky stuff, your e&o and a nice personal umbrella policy should be just fine.  

Insurance would cover it, I would pay the deductible, and no assets would be lost.If you are in an area like San Diego where people are more likely to sue, a judge is more likely to find you guilty, and the payout is likely to be higher, then you may consider an umbrella insurance policy.

Expected cash flow should be your best projection of the cash flow and should have a vacancy estimate, PM costs, Cap expense estimate, maintenance estimate, any utility costs, and misc fees that often are calculated over the sum of RE investments such as LLC, umbrella coverage, office expenses (space/help/equipment), car mileage, etc. 

Facebook even considers promoting your Airbnb to fall under the housing umbrella and, therefore, is considered a Special Ad.Since you still want to target your audience, you have three options: Facebook Core Audience, Facebook Custom Audiences, and Facebook Special Ads Audience.

If it is a small multi (2-4 unit) and you want some additional personal protection, you can ask your insurance agent about getting an umbrella policy to protect you above and beyond what your property insurance will ... it will not be very expensive or add any complexity.

@Greg Scott were you able to get your Personal Umbrella policy to go over the Lloyds policy from REI Guard? 

If your combined net worth is more than $1 million, then purchase an umbrella liability insurance policy to protect your net worth.  

Need to ensure you an umbrella insurance property, naming your 4 plex and you're upcoming duplex on the policies.

If you do not already have an Umbrella policy (provides additional Liability coverage if a covered claim exhausts the limits of your Home, Auto, Dwelling/fire, ... policies) you may want to consider adding it. 

We have an umbrella policy up to $1,000,000, so I wasn't concerned about doing that.