Is this driver liable?

If the metal was lying in the road an was unavoidable, I would say no. The driver must be negligent to be liable.

Can I change my insurance policy right after an accident?

The policy provisions in effect at the time of the accident control.

Can the judge/prosecutor see expunged records?

Your "obtaining money by false pretenses" charge which was reduced to trespassing is probably not eligible to be expunged as you were not acquitted...

It usually does not make a difference if you are on a "highway." I assume OH is the same.

What kind of lawyer should I get?

Any personal injury lawyer can handle the claim, but I'm sure he/she won't take it on a contingency fee basis. They'll charge an hourly or flat...

No. If you don't file a notice of appeal within ten (10) days, you can't appeal.

My car was in an accident and now deemed a total loss. The insurance mailed me an settlement that I don't agree with.

Just because they mail you a settlement doesn't mean you have to accept it. You can still dispute the amount. Don't cash the check or accept it....

Is it a good idea or worth it for me to hire an attorney?

Yes, you should hire a personal injury lawyer. Most will take the case on a contingency fee basis, which means they don't get a fee unless they...

Who will receive the settlement?

If the case is settled prior to your 18th birthday, the funds will be placed in a trust account for you.

Our car was stolen from our house and involved in a hit and run our insurance had lapsed.

If your car was stolen before the hit-and-run, you shouldn't be liable.