Captain Phasma team

I use a 4* Phasma, and yes, Dooku's bonus attack does proc Phasma's leader ability, so if no one comes to help with the first strike, than the bonus attack gives another chance for an ally to lend a hand. So it would make sense that your Leia would be able to do the same thing, but it does not work on counters sadly, Dooku's been attack enough times where someone should have helped him with his retaliation strikes.