Who is Idabel Thompkins from Other Voices, Other Rooms and what is their importance?

Idabel is a girl Joel meets on his first day traveling to Skully's Landing. Idabel is the twin sister to Florabel Thompkins, whose family lives close to the Landing. Joel's first sight of Idabel is her throwing rocks at the barber shop in Noon City with the barber offering Joel money to apprehend Idabel for punishment. Later that day, Idabel presents herself in the local restaurant where Joel sips a soda, and demands to know Joel's identity. Joel encounters both Thompkins girls on his ride to the Landing and initially prefers Florabel for her long hair and feminine ways, but eventually is drawn to the tomboy ways of Idabel. Idabel spends time cultivating a friendship with Joel, who is somewhat romantically attracted to Idabel, but Idabel rejects even the slightest overtures from Joel. Eventually the relationship balance alters and Idabel adopts an even more masculine presence and dominates Joel both physically and emotionally. It is clear that Idabel struggles with her sexual preference and identity and finds herself attracted to a female midget at the carnival. At the end of the story, Joel's affections have transferred to Randolph and Joel rejects any attempts at any further communication from Idabel.