At the moment it is yes to your first question, they should get a "fastpass" saying 1 person + 1,
As to the second part, we don't know for certain when it comes to Genies+ (we only know the info released by Disney, the rest is speculation until Disney confirms it) I do know that when I was doing child swap back in 2017, we couldn't use Fastpass and Ride swap at the same time. For Star Tours, we had Fastpasses, so we had 2 people wait with the child whilst the rest of us rode, then those that rode was with the child whilst those that waited beforehand rode. When the time comes, it is always good to just let the cast member know at the front of the queue what is happening in case the fastpass window closes