Sounds a bit confusing.

O is a Business Class Award Seat
I is a Business Class Upgrade from Economy Seat

If this is a non-revenue (except taxes) Mileage Plus Award, the entire booking should be in O.

In any event, an A319 does not have Business Class and that portion of the trip would be provided to you in Domestic First. You didn't specify the aircraft type for your ORD-LAX segment. Hopefully you're on a 3 Class 777 or 747 so you can really enjoy the Business Class experience.