Few questions regarding upgrading to AP, Fall Early Entry, etc.

[Volunteer]

Hey people, I looked through the sticky's and searched a bit but I couldn't find any clear answers to my questions. I'm hoping someone here can answer these questions for me, I really appreciate it! Here goes:

1. I have a two day park to park pass that I'm planning to use in September, however I am interested in upgrading to the preferred pass. Can I call Universal now, and upgrade my physical ticket I have now, or will I only be able to do this at the gates of the park? For what it's worth, I bought the tickets from Undercover Tourist and I'm expecting to pay the difference between the face value of the ticket (178.99 per the USO website) and the preferred pass (294.99).

2. Once I have my pass upgraded to preferred, I'm reading that during September there will be early entry for pass holders to US (think this is unofficial at this point). I will have a preferred pass, but my mom will only have a two day park pass. Will I be able to bring her in as a guest even though she's not a pass holder?

Thanks again for the help. If I left out any relevant information, ask me and I'll fill in the details.