1 = I answered this on your other post
2 = J(John Proctor) and E(Elizabeth Proctor) had a servant girl (A(Abigail)), but E fired A when E found out about J's affair with A; A wants J to herself so she accuses E of being a witch.
(I hope that's not too complicated)
3 = She starts screaming because she hears a church song and can't bear to hear the Lord's name.