There are no S supports or anything, even for Alear. With that in mind, it is unlikely any of the minor romance events from Three Houses are in, either. It is likely that romance only exists as paired endings, similar to the pre-awakening games. How many there are or who has paired romantic endings with who won't be known until people who have the game early start beating the game, and/or start datamining it.
Also worth noting that all supports seem to go up to A, unlike three houses.