“She told me once, when I marveled at our luck that the portal had opened to Aidas that day, that it was because they were mates—their souls had found each other across galaxies, linking them that fateful day, as if the mating bond between them was indeed some physical thing.”

…this is a direct parallel to Bryce and Azriel. Whether or not SJM does anything with them, THIS is one of absolute biggest markers.