Short answers, pulled from the story.
Plato's Laws is a twelve-book dialogue in which an Athenian Stranger, Cleinias of Knossos, and Megillus of Sparta walk from Knossos to the cave of Zeus on Mount Ida while devising laws for a new Cretan colony called Magnesia. The dialogue covers government ethics, criminal law, religious law, education, and the role of soul in the cosmos. It is Plato's last and longest dialogue.
The Laws is the only Platonic dialogue in which Socrates does not appear. The conversation is led instead by an unnamed Athenian Stranger. Some scholars connect this absence to Plato's later period, particularly his failed attempt to guide the rule of Dionysius II of Syracuse, events alluded to in the Seventh Letter.
Magnesia, the hypothetical city of the Laws, allows private property and private families, and is governed by written laws. Kallipolis in the Republic abolished private property, arranged shared wives for the guardian class, and operated without written law. The Laws describes Magnesia as "second best," not because Kallipolis is the ideal, but because the ideal city would be fit for gods and their children.
The tenth book argues that soul has both explanatory and ontological priority over corporeal things such as earth and fire. Plato reverses the view of the natural philosophers, who held that matter exists first and gives rise to psychic phenomena. In Plato's account, soul is a self-mover that supervises the cosmos, and corporeal things are to be explained in terms of soul.
Aristotle was critical of the Laws. He thought the proposed figure of five thousand citizens fit to bear arms was too high, arguing it would require an impractically large supporting population and territory. He also identified a problem in fixing the number of households while the number of children grew. His analysis of the Laws shaped large portions of books seven and eight of his own Politics.
The Epinomis is generally considered to be the work of Philippus of Opus. He wrote it as a direct continuation of the Laws, using the same three characters: the Athenian, Cleinias, and Megillus. The views of the Athenian in the Epinomis deviate from those in the Laws on some points.