Yes, they are complementary, but no more upgrades for companions (EXP did not have, but US Chairman's did). I will be booking travel with my 4 year old DD (just the 2 of us, domestic). After about 10 minutes of checking, the preferred line told me that if the travel is on AA metal I can use my upgrades to upgrade us both, but getting her upgraded (using any type of upgrade in my "bank") is not an option on US operated flights. In order to be sure we are seated together I have to call after booking and have them block me from being upgraded.
From what I was told the 500 mile upgrades can only be used on AA operated flights indefinitely (was told this by gate agent and preferred desk).