As far as I know it can be kept in the fridge for up to one week.
We have never frozen it. I am guessing that this should be ok. Maybe do some online research.
Yes it simmers for 24 hrs. You will get used to going to sleep with the soup on. The longer it simmers the more minerals will dissolve into the broth.
We use 2-3lbs of soup bones to 4 quarts of water. We add about 4-6 tblspns of Braggs apple cider vinegar. Bring to a boil and skim off the impurities. Thats all there is to it.