I'm hearing of lay people becoming enlightened by the Buddha but did any of them become Lay Dhamma Teachers? When where the first lay teacher(s) of the eightfold path?
o this female during Buddha's time came to my mind. Im not sure how to spell her name correctly ( Khujjuttara) or something like that. She was Queen Samavathi's servant (king Udena). Her back was hunched a little. She used to embezzle money from Queen Smavathi when queen assigned her to buy flowers from the market. One day she heard Buddha's teaching and became a stream enterer. She went to the queen and confessed her crime. Queen forgave her and asked her to recite Buddha's teaching. Since queen could not leave the palace (i assume she stayed in a harem), she would sent this servant to listen to Buddha's teachings (since her deformity allowed her to leave the palace) and come back to tell the queen and her ladies. Lady Khujjutara was one of the earliest lay teacher i could think of.
The problem with "lay dhamma teachers" is that people don't take you seriously as a spiritual guide, if you are still a householder who's unable to give up sexual activities, gold etc. There might have been lay people who taught the Dhamma to small groups, but when there are many enlightened monks around, you don't get much recognition.
In any case, a lay person who has attained enlightenment is a positive influence to his friends and relatives.
Ex: King Pukkusati learning about the Buddha, Dhamma and Sangha from his friend king Bimbisara; Anatapindika influencing his son Kala to listen to the Dhamma; Visakha's influence on her husband's family.