Lilfoot's suggestions are great. As for size, I would definitely recommend that she goes with something smaller. Especially since she doesn't like to bomb. She sounds more like a easy going, hit everything type of rider. 141-143 is her all-mountain size. For her type of riding, I think she should go shorter. I'd go for a 138 for her.
The Feelgood is an excellent board, but it is on the stiffer side. The Feelgood ES is even stiffer. If you are familiar with Men's Burton boards, the Feelgood is a Female Custom and the Feelgood ES is the Female Custom X.
My sister in-law rides the Feelgood. She loves it.
Out of your choices, definitely go for the Feelgood. Avoid the Feather. That board is pretty crap.