You only need 1/4 cup honey, which is plenty of sweetness. If you don't have honey, and you want to make it with sugar, you can substitute the 1/4 cup honey with 1/2 cup sugar. But again – I’d try it with honey first if you can.
Yes, I do all the time! Put the raspberry jam into a mason jar after it's cooled down and then place in the freezer. Tip: If you buy jam in the store, save the glass jar (and lid!) and use for this jam!