look at your deltanet site and get the manage pass riders on the pull down
All the answers are there.
I'm not sure what sort of travel companion you have--live in "non-spouse: or travel companion on yield fare. Dep kids (under 19 and under 23) use S2's--6 per year. Travel Companions on yield fare don't have S2. Theya re a better tnhan buddy pass status because they use your DOH.
Whether they travel with you or not, they only get what they show on travelnet. Going with them gives them no advantage.
Your TC gets one priority and the buddy passes have nothing BUT S4. If she wants to sit with them in coach she has to declare at the gate that she is willing to go DOWN to an S4 to be together. They cannot move up with her,if she gets BE nor can they change seats ANYTIME during the flight.
Same thing for you and your daughter--if you need to split and sit one coach and one biz, you cannot interchange seats enroute.