Questions about Tolkien's Middle-earth family trees

Short answers, pulled from the story.

What is the primary purpose of J. R. R. Tolkien's family trees in his fantasy world?

J. R. R. Tolkien used family trees to explore the etymologies of character names and treat each lineage as a linguistic puzzle waiting to be solved.

Which specific family trees were typed up for The Lord of the Rings appendices but dropped due to space constraints?

The Boffin and Bolger family trees were typed up for inclusion in Appendix C but were dropped at the last moment due to space constraints.

Who are the ancestors detailed in the Elven family trees found in The Silmarillion?

The Silmarillion provides family trees for the Elves Finwë, father of Fëanor, and Olwë, ancestor of Galadriel and Lúthien.

How do Hobbit-style genealogies function within the narrative structure of The Lord of the Rings?

Hobbit-style genealogies mention which Hobbits had children and which did not to give the impression that the story continues after the end of the book.

In what publication does Christopher Tolkien detail the lengthy course of development for all these lines?

Christopher Tolkien later detailed the lengthy course of development for all these lines in Unfinished Tales, The Book of Lost Tales II, and The Lays of Beleriand.