1) In the waypoint's On Activation field, write:-
hint "Waypoint 1 completed"
Is that something like what you want? If not, please explain again, perhaps with an example. It doesn't sound like a stupid question.
2) No, I don't think so, though Armsty's advice is sound - it's amazing what you can discover with a bit of experimentation. The doMove command acts on a single unit who is a member of a group: since only groups respond to waypoints, doMove can't affect a group directly. The equivalent command for a group is move, but I doubt that would do what you want either. The solution is a mixture of switch triggers and setWPPos commands. Waypoints themselves cannot be created or destroyed with scripts.
Note that you can't see waypoints when Previewing a mission in the Mission Editor unless you have already put yourself into Cadet mode. The default for the Editor is Veteran.
Remember also that players playing your mission in Veteran mode won't see the waypoints at all. Never use waypoints to make anything happen in a mission, they are just a bonus for Cadets.
3) What Armsty said.