When Lino comes of age, Gutaf will be in his prime as well, making this the perfect time for an engagement.
As for Vivian...
The reconciliation between the eldest son and a bastard is known as a charming tale, yet family intermarriage has absolutely no relevance to bastards.
Unrecognized bloodlines are tantamount to having no lineage; at least, within the feudal system of the Aus Empire, unrecognized offspring remain commoners unless bestowed a title by their father.
Moreover, even if putting that aside, Edward is not fond of this girl who "clearly has not received a proper aristocratic education."
"Gutaf is truly a good child," Edward said with a smile, speaking to Luo Yan with implicit meaning, "He has a gentle temperament and is of similar age to my Lino. See, how happily they're playing."
Luo Yan returned the smile without responding, certainly having already surmised this.
