Ummm ... let's see. Not sure I know quite what you mean ... but, you see, the choreo and the coach are on the ice together, they chat and bounce ideas off of each other as they go for coffee ... and the choreo (who is also a coach herself) - sees the kids skate day in and day out - and knows them really well. Coach is absolutely out of the picture during the actual choreo - except for calling amusing/caustic/supportive comments across the ice!
In terms of who long it takes for the choreo - I have two kids - one who learns choreo like breathing, and the other one who takes longer. Second child is also a competitive level skater, who skates at a higher level. For the latter: I would say 5 to 6 hours per program, and then the step sequence is done by the specialist coach who works on transitions and field moves. Two programs at that level, a short and a long. For the other kid, maybe 2 to 3 hours, but, she also competes at a lower level - however, the same amount of effort, and intricacy is in the program - it's simply that she picks up choreo at an incredibly (and apparently highly unusual) rate. Other kids with the same choreo may need more, or less time at the same levels ... it's just dependent on the learning curve of that skater.
It's all done in chunks of time - not an hour at a go - 1/2 hour by 1/2 hour and then 15 minute run thrus at the end of the series to ensure that the whole program is coherent. However, there will be periodic revisits to tweak choreo later in the year. The choreo is part of our home club, and is excellent- we benefit from that.
The music is selected for us; she cuts it, and then choreos it. We really don't get any input into, as the coach and choreo select it - however, as the music is always excellent and skate-able, and the kids like it, not a problem.
Because the choreo knows the kids, she knows how to pick music that they can skate to; however, they use a range of music from year to year so that the kid doesn't get pigeonholed as a "pretty" or "dramatic" or "perky" or "latin" type skater. And, frankly, you darned well do what you are expected to do - it's like an dancer in a show: if the choreo says that you are doing X you do X, even if you prefer Y, because the mood and the flow need X. I would never have imagined my kid could pull off some of the stuff that she has done ... nor could she back in the day.
BTW: variations are also possible in your wish list. You can break them down into, say, rockers, 3-turns, choctaws, mohawks etc; and loops (forward/backward, inside outside); twizzles (forwards, backwards) and so on.