For those 10 athletes that didn't compete in indoor track, I'd ahve them do GPP/SPP/Comp. Of course with that small a group I'd be able to give them a pretty individualized program for their GPP phase depending on their individual levels of fitness. For the SPP phase, I'd hope that they'd be more closely on the same page in terms of speed and strength so that I wouldn't have to individualize their SPP program as much.
For the 10 athlete that competed in the indoor season, I'd have a transition period out from their comp phase back into a SPP phase. I guess what I'm sayin is that I'd try to give their bodies time to recover from being beat up and torn up during their comp phase without losing their fitness so that they would be prepared for the SPP phase at about the same time as the other 10 athletes. For them, the period after their comp phase and before the spring SPP would be similar to a GPP but would focus more on maintaining fitness and promoting recovery then an improvment and preparation. I'd be working off the idea that they're already in shape and would just give them a chance to get their focus back for the outdoor season.
After three weeks of this treatment (thats three weeks GPP for the non-competitors, and three weeks of maintenence/recovery for the indoor competitors), I'd take both groups and have them start doing their SPP. I'd have this last about 4-5 weeks, with a transition to comp phase beginning during the 5th week. By this time, we're at week 8 of the season.
Then I'd have them start their comp phase, and continue that through the state meet. This way, they have 4 weeks of being strong competitors, and will have a week of comp phase work under their belts for that 9th week meet, giving them some confidence for the upcoming qualifying meets.
During each phase I wouldn't do anything special outside of the normal goals of those phases, unless it was an individual athlete that was progressing faster or slower than the rest.