It sounds like it IS a rental property even if you are not currently collecting rent on it.
It's not owner-occupied. You don't live there. You need a landlord policy.
Owner-occupied policies cover the OWNER's HOUSE, GARAGE, BELONGINGS, and loss of use if the property is damaged and the owner can't live there anymore, while it's being repaired. It also offer liability (and med pay) for the owner's negligence.
Landlord policies offer coverage for the HOUSE. You can purchase coverage for the GARAGE, a reasonable amount of furniture that you equip the "rental" with (stove, fridge, a/c units, etc), but you wouldn't want to pay as if your furnishings are (at minimum) 50% of the value of your home. It would be a waste to pay for loss of use, because if the home isn't damaged, you don't need to move. You can pay for liability or you can add it to your current home insurance policy.
The coverages are different between the policies. You want to pay for the poicy that will pay you (or your mortgage company) in the event of a loss. Not the one that will be cancelled by the insurance company without any payment (for fraud or material misrepresentation).
