I can tell you that last year I booked 4 saver award tickets for my wife and 3 kids through my UA account, I was not on the itinerary and did not fly, and all 4 received complimentary upgrades to FC on the outbound flight IAD to GUA, but not GUA to BOG. I was told by a UA rep that "because I had the MP Club card", myself and any person traveling on an award ticket issued from my UA account would be eligible for complimentary upgrades. Otherwise, I would not be eligible for such a benefit. I have also traveled within the U.S. on a saver award ticket and received a complimentary upgrade to FC.

BTW - I never saw myself or my family members on the waitlist, I received am email confirming their upgrades. When I spoke to the UA rep, she said that complimentary upgrades on award tickets are available to UA CC holders, but you will not see yourself on the waitlist after checking in, even though you are on the list.