It's the same number as the "PAYER'S TIN" near their address on the 1099-INT. Not sure why TurboTax calls it a FEIN

You could try to find an open post office and just mail it in. Make sure to sign it and stuff

I'm no expert but....They have to do a 1040EZ or 1040 if not a simple summer job situation. When I was a teenager my dad would still count me as a dependant but...