Scholars aren't summoners. I would sooner expect Phoenix as a SMN utility move, though I don't anticipate it given the in-game lore. Despite Bahamut, Phoenix is likely forever out of player hands, at least this early in the story.

At least as a primal, that is. His variant makes a cool mount.

Given the tooltip changes of Summon I and II, Eos is the "healing" fairy and Selene the "support" one, and they both fit this. However I'm a little concerned with their pokemon 4-move nature and how they haven't really been addressed since the release of HW when Selene's awesome spell speed skill was reworked into the current triviality. I'm also a little concerned with the redundancy of Fey Illumination and Largesse, and if having both of them as well as Dissipation is going to somehow cause us issue further down the line. I mean we never asked for more divine seal effects, and yet here we are with three of the bloody things...