1) I don't think women should lead the congregation in prayer or in worship. That is a role that properly belongs to ordained elders, who are responsible for the content as the governing authorities.

2) If any of the women is praying as the "voice of the church" (where everyone remains silent while she prays out loud), I'm inclined to deem it inappropriate. It implies authority over the church. I don't see anything wrong with women putting in prayer requests, though.

3) I'm not sure where I woul draw the line, though my initial thoughts are that sharing is largely anecdotal and personal, whereas teaching is aimed more at developing and applying doctrine or praxis. An elder may share in the course of his teaching, but sharing alone isn't teaching.