The companion you name under the Million Miler program will have the same status as you do in any given year, whether or not you travel together and irrespective of whether the companion now has or doesn't have elite status. Your companion will get the MileagePlus card showing that status but will not receive any confirmable upgrade certificates which you earn as a 1K.

As you point out, the realization of this status won't occur until full integration, likely near the end of the first quarter of 2012.