I am in agreement with you, Grondy, on all points except one:
Now that isn't the same as writing a character
I think that it is the same as writing a character. How else do you think writers create characters? ;)
The Mary-Sue issue.
My defenition would be somewhat shorter: An original character who isn't. Mary Sue is an archetype - all Mary Sues are cut out from the same basic pattern.
This is not to say (in my opinion) that Mary-Sues are necessarily bad. I have read some wonderful romance Fan Fic. even about young helpless damsels in distress being rescued by Elladan/Elrohir/Elrond/Legolas/Maglor/Aragorn/(and even) Gandalf. They were good because the postAuthorID was good enough to pull it off.
I have also read some Mary-Sue fic. that was downright awful. It isn't the formula that doesn't work, it is (sadly) the postAuthorID's writing or in some cases their personal fantasies getting in the way of good writing.
A lot of beginner writers write their first stories about themselves, ie. they insert their own character into their work. They do this because it is easy. We know ourselves better than anyone else and can easily guess how the character (oursleves) would react in a given situation. My personal belief is that all writers need to go through this as part of their 'apprenticeship' as a writer. Later, we discover how much fun it can be to step into the point of view of a person very different to ourselves. Then we begin to really start writing.
I have written short stories (see PT Fan Writings for an example) and parts of my novel from a male POV. It was a lot of fun. Much more fun than Allyssa at her best, but I am not sure if I could sustain it for an entire novel. That is a challenge that I have yet to conquer, but it is most certainly on the dawing board.
The character in my own novel is something of a M-S. She certainly has some of the characteristics! But she fails to find romance, or be rescued, or to gain the respect (or even attention) of anyone very important and she is not very strong. Her role is a catalyst in her world. She is the one who trips over the wheels and gets the whole wagon moving along.
First, is it possible to write an original female character in Tolkien fanfic who isn't Mary Sue? If so, how? With what sorts of characteristics?
Write a character that isn't an archetype? Yes, it is possible, it is just not conventional. Fantasy conventions are probably the cause of the M-S population explosions. It is what readers have come to expect from the genre. But it is not essential. As I said before, it doesn't really matter if the story is a M-S. It is the strength of the writing that is important. If the writing is good enough, the reader will want to read on anyway and that is what the postAuthorID is trying to achieve, an enjoyable, entertaining read.
Sepdet - I didn't think that your character was too Sue-ish, but that is up to you. You know her better than anyone.
My apologies to all for the undue length of this post! ;)