I've done residential exterior service work for years and now do the residential estimates, so I have the upper hand when it comes to evaluating repair cost.

I'm a Project Manager running commercial and residential construction, not a property manager.

  : )There are no 7 year life assets in a residential rental real estate activity. 

We created an LLC for our salon, tax office, residential rentals, and commercial rentals.

Only you can really answer that since it depends on your goals / business plan.If you are investing in residential properties, then more than likely you are working with a Realtor, a member of the National Association of Realtors. 

You can only take so many residential loans

Last year a short term rental law that limits short term rents in residentials in San Diego was passed then rescinded.I was wondering if that legislation is enacted in the future, will that concern MF (>= 4 units) also.

We have property insurance for the overall building and I believe it is standard practice that commercial tenants pay for their own property insurance for inside their walls (just like you would have renters insurance in a residential unit).

You can charge higher rent (~$50/mth); the tenant pays some - or perhaps all - the operating costs (electricity/gas, water, DHW); and you can use residential machines (A high-efficienty front-load laundry can be found for $1000.00 or less).   

It's currently a sellers' market, and finding residential properties that cash flow without substantial down payment will be a challenge.