Pay 2 Force Two of your Characters get each other's activated abilities in addition to their own until end of turn. You may play this card anytime any of those abilities could be played.
The phrase "anytime any of those abilities could be played" refers to the play point for the abilities in general (including during the build step), not for the particular instance of the ability on the designated units. For example, if Instill Doubt is played on Chewbacca (A), then Chewbacca (A) can't activate Retaliate. However, at the point in the game sequence when Retaliate could be played, Don't Get All Mushy could be played to give Chewbacca's Retaliate ability to another unit.