Hi tgod288. Welcome to Flyertalk.

Some of the basics:
Assuming you are on a revenue (paid) ticket, you will be automatically added to the upgrade list for any eligible flight. Assuming you are flying from MCO to a hub to catch your TPAC flight, then your first leg will be eligible. Don't count on the upgrade being given. They have gotten pretty rare.

United does not offer free upgrades on Intl long-haul flights to Plats, so you will not be on a list for the TPAC. You could apply for an upgrade using Miles + Money. The amount of money depends on what fare class you purchased.

You will be eligible to enter either the United Club or ANA business class lounge at NRT. (And at the United Club before your TPAC as well).

Economy on ANA is a bit cramped, so be ready for that.