Joseph as a dummy! - Nativity scene from Backwell Church, Somerset - I attended the linked Primary School
Jesus's was the legitimate son of Joseph, and Joseph had a strong claim to be the rightful King of the Jews by lineal descent - that is the meaning of the detailed (different) lineages given in Luke's gospel (at the baptism of Jesus) and Matthew's gospel (at the opening); and by the many references to Jesus being born 'of David's line) and being King of the Jews (after Joseph had died).
Therefore the Nativity story should begin with Joseph - living in exile but not obscurity; well-known to be the 'true' King of the Jews; and working as a skilled craftsmen of the 'middle-class'.
In other words, the story needs to establish that Jesus was born heir to this claim to be the real King of the Jews; and in this sense already famous at the time he was born.
In other words, the common notion and depiction of Jesus as born-into poverty and obscurity is absolute nonsense; and makes the Gospels incoherent - when we find, at the end of Jesus's life, the Jewish and Roman authorities treating Jesus as a potentially very dangerous political threat.
That was plausible; on the basis that Jesus was heir to the Kingship, and could plausibly have rallied a revolutionary army to restore him to his rightful political position --- quite apart from - and in addition to - Jesus's various blasphemies, breakings of The Law, the possibly-demonic/ dead-raising (necromantic) miracle; and his denial of the legitimacy of the authority of the Jewish people's existing priests and rulers.
Joseph is necessary to set-out the proper framework for understanding the life of Jesus; and that should especially be reflected even in the simplest account of The Nativity for kids.