If you no longer have the vehicle and you don't intend on insuring a new vehicle with the same company, you should be able to back date cancel it to the day after the accident. Your best bet is to call your carrier’s customer service line and see what they can do for you.
It is best to wait and confirm whether the at-fault party has insurance or not. If they do, the insurance adjuster can take a look at your vehicle and collect the necessary data to move forward in the claim process.
If your insurance company has deemed your vehicle to be a total loss, you can expect them to pay you the actual cash value of your car minus your deductible. See more about total losses in car insurance here.
Your gap coverage should still cover the $2,000 owed on the loan regardless of what happens after that. I would definitely check directly with your insurance company to make sure there is no stipulation that prevents this if you choose to buy back the salvage title.
If your daughter was the listed driver and the accident was logged correctly, most companies won't charge that against you. If you are looking to switch insurers and her accident comes up on your claims history, I would obtain proof or confirmation from that company that the claim wasn't yours so it can be cleared.
Gap insurance will only cover what is left on your loan after an insurance company pays out. Gap coverage is best purchased if you are going to have a difference between the loan amount and the value of the vehicle.