Makes sense why the children only get shared quotes with their fathers (and Azura with Shigure respectively) considering that the children of Fates are tied to their fathers. Their mothers are dependent on who the player chooses to pair up so would be a lot of hassle to create voicelines for all the potential possibilities. That’s why Awakening children (outside of Lucina with Chrom) share crit quotes with their mothers only, as their canonical parent is their mother in that game.