I have just gone through all the Little Rascals talking shorts. Watching them in chronological order shows you how it evolved.
The early ones had Farina getting most of the laughs. Chubby was funny too. Wheezer was the mischievous little brother but soon had a few leading parts in the films, such as Dogs Is Dogs (1931) though the scenes with his mean step mother are pretty disturbing. The series really picked up when Jackie Cooper joined, he was in some of the best of this period like Teacher's Pet (1930) where he first meets Miss Crabtree, "School's Out (1930) the kids give some funny answers to Miss Crabtree's questions and Love Business (1931) has Jackie and Chubby both in love with the teacher. Cooper was so talented he went into feature films and got nominated for an Oscar for Skippy (1931). Derby hatted Stymie was a real scene stealer during this time.
My favorite Spanky is introduced in Free Eats (1932) as an adorable toddler, he later become the grumpy kid who could expertly toss off one liners and finally became the leader of the Gang, often coming up with ideas and schemes. Dickie Moore was te lead in some of the best of this period like Free Wheeling and Birthday Blues from 1932 and Mush And Milk (1933). He was soon snatched up for feature film too. Alfalfa was funnier in his early films like Beginner's Luck, Teacher's Beau, Sprucin Up all from 1935. He had his front teeth missing and sang country and western tunes, this was before he became the squeaky voiced crooner of later films. Buckwheat was very funny during this time too, he was later teamed with Porky as the two little kids who were usually smarter than the older ones. Buckwheat's speech became easier to understand in later films but I still can't understand what Porky was saying.