1. Both answers could have some legitimacy, as the evidence is not 100% clear. It is more likely, however, that the sleep was a reward. Rip's long sleep means that he has missed the war, with all the suffering, trauma, death and hardship that a war brings. Moreover, despite not having to contribute to the war effort, Rip enjoys all its benefits when he wakes up. His long sleep also means that he is free from his wife. Finally, it seems like Rip's life does not change much when he wakes up. He is accepted by his family and is able to settle into his regular routine easily.
2. The setting of the story is important because of the element of independence. Rip has been awarded by being transported to a moment in his life when he has more independence. He does not have to take care of his children anymore, and he has been liberated from his wife. The theme of independence within his family life is mirrored by the theme of independence that the Thirteen Colonies have acquired.
3. It is likely that the story is a comedy, as Rip is not greatly inconvenienced by his long sleep. In fact, when he wakes up, he goes back to a routine that is very similar to the one he had twenty years before. He, therefore, represents a link to the past. He serves as a way to highlight the importance of keeping links with traditions and ways of life of the past, in particular in a nation that is quickly changing. This is one of the main lessons the story wants us to learn.