I didn’t realize I can create a Tween using Tweens.sequence(actionToPlay, doneTween) and avoid calling the actionSequence() method altogether. It appears to work now. Thanks!
So it seems like this is finally a good solution for making a non-looping animation with a doneTween.
Another idea could be that we add a boolean propagateMask field to BaseAction and set it to true by default. If we want to provide our own mask then we can disable propagation. Note that BaseAction is the class JME uses to wrap any other type of tweens including sequence, parallel,… to be playable by AnimComposer.