Against the dryax (first time I've made it to Tier2), when starting a battle, only 3 units are summoned, not 4, so I end up not having Yoda & Chewie on the field.
I can't see anything where it indicates that this is expected in the notes about the game mode, so this leaves me (us?) hindered above Tier1.
So reading the description of the summons, it says, "At the start of battle, *up to* 4 enemies are summoned based on this unit's Era Level and the Lowest enemy's Era Level in the following order:" and then Yoda and Chewie are at the bottom of the list.
Whether this implies there's a percent chance based on your era level or if you are locked to just three summons without levelling up, I'm not sure.
