Can't help with the geese questions, but Shropshire sheep might be an option - they won't touch the trees provided there's grass to graze, and if they do take an interest will only eat the leaves and not the bark.
We run hens under our young orchard, on a rotation. They manage to keep the grass down for most of the year, but from about now until August I'll be cutting the grass in the empty areas every couple of weeks.
HTH,
Dan