These should not be your primary funds for rental property emergencies, but they may be supplemental in extreme situations.I would say for one property, keep around $10,000 minimum in reserves.

A great broker will talk your thru the process, discuss your risks/coverages and help you know if you will be able to get insurance on the property or if any updates will need to be done.

You will want to shop your options to see what makes the most sense for your situations as prices and coverages for these products may vary in each market area.

-Ordinance and law - if you have this coverage and you should unless super new, it will cover additional costs to bring to code up to 10%, 25% or 50%.

My objective to to develop a portfolio of multi-family units that will supplement me in retirement (within 3 - 5 years) so Cash over Cash return is key for me. 

I know that they have changed just like some of the other carriers but lately the coverage that they are willing to extend for the price is superior. 

But they do have minimum coverage outside of the umbrella.

I currently have coverage through my employer.

It's bad coverage & very expensive but you can get that insurance through any insurance broker, make the repairs and then get regular insurance provided your lender will allow it. 

And what coverage if so?