I would recommend Warm and Natural batting.
I think more ties are better because the more ties, the less stress there is on each one.
My daughter's dogs shredded a quilt I made for her. I am also suggesting throwing a sheet over the quilt to protect it from the dogs' paws and claws. They did not chew on it or anything like that - it just got worn quickly from their getting off and on it. The dogs were setter/lab size.
Some people use perle cotton or crochet thread for their ties.