You will need your home owners insurance. That is the only insurance you will need because if something happens it is on your property and you will be covered under your home owners policy. When you rent a backhoe there will be an additional charge for insurance. You can either pay the charge or not, but you have to be careful as to what liability you're assuming when you sign the rental agreement.
Not likely. The owners liability coverage is generally an option under the home property insurance policy. I don't know of any insurance company that would sell Liability as a stand alone coverage for a home.
Professional Liability Insurance.
Rental insurance is usually for when you buy an apartment or a condominium. It is also a good idea to buy it with your vacation rental home since you do not know what damages your vacation rental home may undergo, and one day a catastrophe may destroy it. You will want to be insured for that.
As of this date, liability insurance is not required but SB2029 requires that home improvement contractors disclose to home owners in writing to any potential customer whether or not they carry commercial liability insurance.
Please clarify the type of "rental coverage" that you mean. There is, for example, rental insurance available on rental cars, and rental coverage that one buys on personal belongings when living in a rented home.
Rental insurance is a very wise insurance to have. This can cover loss and damage just like a regular home insurance even though you are only renting.
The liability portion of your home insurance policy provides protection in the event someone asserts a claim of liability against the homeowner for damages or injuries.
Personal liability insurance provides additional coverage to other insurance policies. Without personal liability insurance, any thing that one's home or car insurance could not cover, one would have to pay out of pocket. Personal liability insurance will cover those fines.
Check you policy to determine if you have rental car insurance. Some credit cards also have rental car insurance. http://www.theglobeandmail.com/globe-investor/personal-finance/home-cents/do-you-need-rental-car-insurance/article1994097/
You home owners liability insurance should cover it.
Consult LOCAL insurance companies.