HONK/SEAL CREAK Noise...Normal???

Definately not normal. Tell your dealer you show you another prius on the lot do it.
Whats wrong with these guys?

PA Lemon Law
Under the law, the manufacturer must, at no cost to the purchaser, repair or correct any defect which substantially impairs the use, value or safety of the vehicle and which occurs within one year after delivery, or 12,000 miles of use, or the term of the manufacturers express warranty, whichever comes first.
If the defect cannot be repaired after 3 attempts, or if the vehicle is out of service for a total of 30 calendar days for repair, you may be eligible for a replacement vehicle or the refund of the purchase price, less a limited allowance for use.

I'd focus on the pedal not returning properly as a safety issue.
Heres a link to the full law:
Pennsylvania Lemon Law

 

Yeah, that's messed up. Maybe weather related? Has it been happening more or less frequently with the temperature drops?

Either way, it's a problem. Did you contact the zone rep yet? If they aren't getting anywhere, you might have to go to arbitration. Even that isn't binding on you as a customer. There's a lemon law hotline at 1-800-441-2555, but I doubt it'll get to that point. Your dealership may be dragging their heels, but I doubt your zone rep will.

Let us know how it turns out!

 

You heard/saw it on another car?

 

Almost sounds like thumping a high tension string? I have had my GIII for over a year and I don't recall hearing that particular noise. Let alone having the brake pedal not return to normal position. Absolutely does not sound normal to me.