General Insurance Is there a temporary insurance policy while I'm test driving a used car to protect me before I actually buy it?
There really isn't a global policy that can be used for what you are needing, nor does "temporary insurance" exist. The good news is most insurance plans are paid month-to-month and have very minimal penalties for canceling — if any penalty at all.
Most Recent General Insurance
Roadside assistance covers towing but it won't cover your car being towed by someone else. Your insurance company will not cover the cost of your car being towed from parking in the wrong location.
The drivers need to be insured on the policies of the people who own the vehicles that are hauling the trailer. Since the trailer is already insured, there is no additional insurance required.
Coverage & Claims
I'm sorry for the difficult situation. If the towing company damaged your vehicle, then they would be responsible for paying for the damage.
Unfortunately, this would be an example of insurance fraud. Most likely, your insurance would deny this claim anyway because of the correlation between the date of the added coverage and the date of the claim.