I was just thinking about how difficult it might be to (fairly) pick a line-up for the team event. If it were up to me, here is how I would pick the teams:

Singles:
SP: Winner of the SP at Nationals is GUARANTEED a spot. Second spot picked on basis of SP results throughout season.
LP: Winner of the LP gets a spot. Second spot picked based on LP results of season.

Pairs and Dance:
Top two teams from Nationals get picked, one skates SP one skates LP at USFSA's discretion.

Would you use different criteria?