Ummm... potentially a reasonable assumption EXCEPT... that I don't know for sure that they keep it so that the FIRST session is necessarily alphabetical from "A"... in other words, so that the same countries wouldn't get penalized from a schedule standpoint (either with too early practices ALL THE TIME for the AZER... and very late practices for the end of the alphabet) if I recall correctly (and I am definitely fuzzy on this) they may pick some middle of the alphabet group, and move from there. They might also alternate days.... Bottom line - I don't know that you can make that assumption. Better to check the actual schedule.
One other thing to try not to get too disappointed over is the fact that not necessarily all of the athletes show up on the "Sunday" for practices. Especially skaters who are in the same time zone as the event. It is a long week, and you often hear about athletes taking the strategy that it is more important for them to either rest at home longer or train in more familiar, less scrutinized settings than the "official practices."