No, since the jewelry has no sharp edge and is smooth there is no reason to remove the jewelry. Some people may notice discomfort if their partner is wearing really large jewelry though.
Yes and no. The piercing does cause some of the milk ducts in the nipple to reroute or close but since a majority of the duct are in fact located in the areola the piercing should not effect breast feeding. I would like to stress that if the piercing is not well healed or well not be by the time of birth, remove them to reduce the chances of infection and other problems during breast feeding. Not only because why create a problem if you don't have to but because you don't want to create a situation where you are unable to breast feed. Lastly you should consider changing to a Barbell or other jewelry that is easy to remove. Having a 14g 5/9 ring in a new born's mouth seems not only intrusive but dangerous. For more information go to The Nipple Piercing Page.
It all comes down to hands on experience and I don't feel it is ethical to experiment on clients. The piercings that I do perform I do have a great deal of experience doing and a complete understanding of placement and technique of that piercing. I'm a strong believe that if you don't know what the hell you are doing you shouldn't do it and second hand knowledge is worthless. I'm more then happy to refer anyone wishing to get those piercing to someone that has a great deal of experience with that piercing.