I would recommend not using abomasnow unless mega evolving, and celesteela is not ideal. However, I understand if u have put lots of effort into training them and find them quite powerful.
Ninjask would be a good 6th pokemon. I always use it until I find something better, as it is very useful.
Very good move sets :) except for ingrain, which is probably best substituted for a move like rock slide to compliment abomasnows weakness to fire and flying. with an abomasnow that is relaxed or something that promotes def, then feel free to use ingrain