Which characters in the story "Miss Esther's Guest" by Sarah Orne Jewett are round or flat, dynamic or static?

There are only three characters in Sarah Orne Jewett's short story "Miss Esther's Guest," and they are the protagonist Miss Esther Porley, the minister's wife Mrs. Wayton, and the guest Mr. Rill.
Miss Esther is a dynamic character whose characterization is quite round. Old-fashioned, genteel, kindly and rather nervous, Miss Esther is an "old maid" who lived with her mother until the latter's death some three years prior to the setting of the story. At sixty-four, Miss Esther has never lived with anyone other than her mother, and taking in a guest represents a major change to her routine. As she says to Mrs. Wayton:

"I've thought and flustered a sight over taking this step [...] I had to conquer a sight o' reluctance, I must say. I've got so used to livin' by myself that I sha'n't know how to consider another. "

Miss Esther has been very lonely since her mother's death, though, and is determined to try and remedy that loneliness. She signs up with her parish to be a hostess for the "Country Week" scheme, which sends working-class city-dwellers into the countryside for brief holidays. Miss Esther misses her mother badly, and recalls to Mrs. Wayton that her mother used to love having company in the house:

"Mother never was one to get flustered same 's I do 'bout everything. She was a lovely cook, and she'd fill 'em up an' cheer 'em, and git 'em off early as she could, an' then we'd be kind o' waked up an' spirited ourselves, and would set up late sewin' and talkin' the company over [...] I make such a towse over everything myself, but mother was waked right up and felt pleased an' smart, if anything unexpected happened. I miss her more every year[.]"

Miss Esther wants to bring some life back into her house, but she is also anxious about letting a stranger into her home. She tries to compromise by requesting that the guest be an elderly woman, similar to her late mother, so that her life will not feel too disrupted. She paints this as being considerate of the comfort of her guest:

"I should know how to do for a woman that's getting well along in years, an' has come to feel kind o' spent. P'raps we ain't no right to pick an' choose, but I should know best how to make that sort comfortable on 'count of doin' for mother and studying what she preferred."

This request is however for Miss Esther's own comfort. When the Committee for the Country Week sends a man instead of a woman, Miss Esther's plans are thrown into momentary disarray, and her anxiety spikes:

She thought of the rye short-cakes for supper and all that she had done to make her small home pleasant, and her fire of excitement suddenly fell into ashes.
"[...] I expected an old lady," she managed to say, and [she and Mr. Rill] both stopped and looked at each other with apprehension.

After a tense moment, Miss Esther surprises herself by accepting the unexpected turn of events and deciding to make Mr. Rill welcome in her home. This is a leap of faith for Miss Esther, a nervous person who admits that she finds change difficult. It works out beautifully, however, as she and Mr. Rill discover that they like each other very much. The guest Miss Esther so feared to take in ends up asking her to marry him, and the story ends with Miss Esther confiding to Mrs. Wayton that Mr. Rill is arranging to move to the village permanently. The "pleading old face" Miss Esther had the beginning of the story is now "quite coy and girlish" and she is full of happy anticipation of the new things to come.
Mrs. Wayton, by contrast to Miss Esther, is a very flat and static character. She does not grow and change over the course of the story, and serves mainly as a a friendly ear for Miss Esther's thoughts. She is described as " a pleasant young woman with a smiling, eager face," who listens to Miss Esther's worries about the twin fears of loneliness and change, and enables Miss Esther to sign up for the Country Week scheme as a hostess. Miss Esther confides in her at the end of the story that she and Mr. Rill have developed feelings for one another, and Mrs. Wayton expresses her happiness for them both. Apart from these short conversations, however, she does not appear in or influence the story.
Mr. Rill is less developed as a character than Miss Esther, but can also fairly be said to be dynamic and round, as he, like Miss Esther, changes over the course of the story. He is very similar to Miss Esther in a few ways, being a well-mannered, rather reserved gentleman who has never married and lives alone. Like Miss Esther, Mr. Rill is lonely, but he has resisted suggestions from his friends about changing his life:

There had been occasional propositions that he should leave his garret altogether and go to the country to live, or at least to the suburbs of the city [...] But so long as he was expected to take an interest in the unseen and unknown he failed to accede to any plans about the country home, and declared that he was well enough in his high abode.

His friends finally prevail upon Mr. Rill to take a short vacation with the Country Week scheme, because as Jewett notes:

He had lost a sister a few years before who had been his mainstay [...] he was very lonely and was growing anxious[.]

Mr. Rill is just as apprehensive about this change to his routine as his hostess, Miss Esther, is about the change to hers. They are both determined to make the best of the situation, but they are also both thrown when they meet each other—Miss Esther did not expect a male guest, and Mr. Rill did not realize that he was an unwelcome surprise to his hostess, thinking she had been informed about him. Mr. Rill is willing to stay somewhere else to avoid causing problems for Miss Esther, and for a moment, both characters look about to retreat back into their lonely little worlds:

"I do declare!" faltered the old seal-cutter anxiously. "What had I better do, ma'am? They most certain give me your name. May be you could recommend me somewheres else, an' I can get home to-morrow if 't ain't convenient."

Miss Esther decides to take the surprise in her stride, however, and she and Mr. Rill get along wonderfully. By the end of the story, Mr. Rill has decided to make arrangements to move to the countryside, uprooting himself from his old life in order to start a new one with Miss Esther. As a token of the change in his outlook, he leaves his pet finch with Miss Esther when he leaves her to go make his arrangements. The bird is symbolic of the new presence in Miss Esther's life, and of Mr. Rill's intention to come back to Daleham to stay.
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