Trip Advice: ORD to HKG

Hi All,
I am new to the forum and wanted some advice on a trip I am taking to Hong Kong from Chicago on UA. I apologize for my general lack of knowledge on the topic and if this is not the right place to post this information. Here is my info:

-Flights are ORDtoHKG UA895 and return UA896
-I currently do not have status on United or any other airline.
-I have about 50k miles with United
-I have a MileagePlus Explorer card
-Tickets are already booked through business Amex
-I am flying Economy

Other flight plans for the year:
-I am planning to fly ORD to CUZ in July for pleasure. Tickets have not been booked, but I don't believe UA flies this route.
-I am planning to fly ORD to IAD in July for pleasure. Tickets have not been booked.
-I am planning to fly ORD to RDU in November for pleasure. Tickets have not been booked.

Questions:
-Is there a way to get status on United through a challenge or other means? I do not have status on any other airline currently.
-Economy Plus is $123. Is it worth it to book now or wait until I get to the airport?
-First class upgrade is available (waitlist) on the return flight (HKG to ORD) for 30k miles plus $450. Is this worth it?

Thanks,
Vik