Will I need to have an episiotomy with an assisted delivery?

Not usually. I don't know why you are planning on having an assisted vaginal delivery. There are a few fetal and maternal medical conditions that lead a physician to perform a vacuum or forceps delivery. Whether you are going to have an episiotomy depends on many factors including your anatomy and fetal heart rate.
Not necessarily. It depends on the size of the baby and the reasons for doing the assisted delivery. Sometimes you don't need an episiotomy, sometimes you do. Often that decision is made at the time of the assisted delivery.