It is all about intimidation with geese. The cats here, once they see the geese heading toward them, snakey neck, hissing, ruffled feathers -- they know that it is time to be somewhere else. If the cat is crazy and doesn't run, and they actually get their beak on her -- they'll hold onto her and beat her with their wings and goose wings hurt! At eight weeks your geese are close to full size too . . . I think giving them some practice watching the cat will reassure you that the cat isn't going to stick around, and that your geese remember what to do with suspicious little animals.
When your geese are nibbling on you, they are being curious with a flock member -- it is different than the bites that they give nasty intruding animals (or people -- I've gotten some nasty bites from ganders protecting their nests). If they do start biting hard, be sure you tell them no, just like a puppy!
Sounds like you have a nice safe coop for them during the night too. We have coyotes instead of foxes, but sounds like they hunt in a similar manner.
My ducks are my comedians - they are so funny. Every time something strange is around you can find them as close to it as possible, staring intently. I located the raven that was stealing eggs by the ring of ducks around the tree he was sitting in . . . sigh.
