@Mohammad Mahir Khan The first things you should really learn are the costs of owning a rental, do research on property management, property taxes, and insurance as those are all but guaranteed; then branch out from there. 

Is there a certain liability insurance coverage I should have on the commercial property? 

I have seen some insurance people say you can cover this just as well by getting enough liability coverage...which I also have (for the LLC) and may be  true. 

You need to insure your success from the beginning. 

What's the best way for us to protect ourselves as investors, we can't get title insurance with a Quitclaim deed right?

I'm building a new house and was told to get builders insurance. 

Be aware that tennats will often refuse to pay their last months rent when leaving so be prepared to begin th eeviction notification immediately to allow you to collect and insure they are out as agreed.

. $58 a month seem a bit high for insurance also.

Seems it is not in coverage area or cost prohibitive due to milage.

However, I also look at expenses per unit (as a secondary examination), to see if there is anything out of order (e.g. market insurance is $200-$300 per door, and even if the overall expenses are 50% of Gross Income, but insurance is $420, than I look into it.