Hi,
Sorry I can't help you with the first part of your question, but here is the answer to the second part from allears:
I have some tickets left over from my last trip to WDW and I think they have some park days left on them. How can I check what's left on these before I go so I can figure out how many days I still need to buy tickets for?
You can find out what is left on old tickets is in person at WDW. Any resort Lobby Concierge or Guest Relations window can scan them and tell you what remains unused on them. The Disney Stores cannot tell you.
Disney Ticketing is once again allowing telephone inquiries to check unused days on tickets. Call 407-566-4985 Monday through Friday from 9:00 a.m. to 5:00 p.m. Press option 2 when prompted. Be aware that this availability could once again change at any time and may vary from CM to CM.