The gymnasts going to Gymnix should already know and will come packed to camp. As always, they have to be healthy and verify, but it should not be a mystery to them. Traditionally, you are selected at the camp 2 months before the event and told after that camp if you are verifying for a competition or back-up spot at the next camp. You verify for those positions at the camp immediately before the event.
The way the 2020 calendar is set up, I would expect the 3 on team to be going to Gymnix and Pac Rim, and new junior athletes to be added to team to compete at Jesolo. That's a GUESS based on the calendar.