The question of genealogy (spoilers) (Assassin's Creed: Odyssey)

Good afternoon. Recently passed the game (except for DLS about Atlantis). I had two nagging questions.
Actually the first question - who is the son of Leonid? Yes, I know who is in reality the son of Leonidas, Wikipedia to help me. But in the beginning of the game, during the battle with the Persians Leonidas shouts at him saying my son fights better than you" (something like this). But the logic of the game Leonid daughter Merrin. Because Pythagoras, of course, cannot be his son, in principle, as much older than Laziness. So why for the whole game, we never hear about the brother Murrin? Where he is, who he is and so on. Weed?
The second question. If between Alexios and Cassandra, the difference in 10 years, the youngest child is also the son/daughter of Pythagoras? How could it be that at the moment of conception, the youngest child, the eldest is already 10 years old, he lives with Nikolaos and a mother, and the mother then goes and spikes again with Pythagoras? As the eldest child and has not seen him? Or then it turns out that Cassandra and Alexios - summary? And one of the kids from town?