Hi,
I drink buttermilk. I use it to make Irish soda bread, buttermilk pancakes and buttermilk biscuits. You can marinate your
chicken in it. You can use your buttermilk to make more buttermilk.
As to your other question, I would estimate you can freeze it. When you defrost you may find some separation which stirring with a whip will reincorporate it. Of course, whatever you do please report back the results because this place is just one big learning experience!
Regards,