Does Seamus Finnigan die

Answer 1

No, in the books it is not stated that Seamus Finnigan dies. He is not seen much in the later books but he is present near the end of the seventh book and is not one of the characters stated as dead in the end.

Answer 2

Seamus Finnigan's life after the Second Wizarding War is unknown. After the Battle of Hogwarts, Seamus was not among the mentioned casualties, and it is most likely that he survived.

May Have Happened:

Seamus Finnigan married Lavender Brown. They had two girls: Cathleen and Briana, both traditional Irish names. Lavender opened a shop called 'WonderWitch', which sold fashionable robes, jewellery and basically magical girly products. Seamus worked in the Department of Magical Games and Sports at the Ministry of Magic, in the British and Irish Quidditch League Headquarters.

* Please note that the second bit has never ever been stated by JKR and therefore can not be considered canon at all.

Answer 3

Seamus Finnigan's future life remains unknown.

Answer 4

Seamus is seen sitting next to Dean Thomas and Aberforth Dumbledore after the battle at the end of the Deathly Hallows. Lavender Brown is seen dead, killed by Fenrir Greyback, when Harry leaves to give himself up to Voldemort.