Storing (freezing) spare falafel: cooked, shaped, or just the mix?
The best way to freeze felafel batter really is formed into small balls, but not cooked.  Then you can toss the partially thawed balls into hot oil without further fuss.  Because the balls are fragile, as you noticed, that means lining them up on a cookie sheet and freezing them that way, which you may or may not have room for.

I have not tried freezing a mass of felafel batter, so I don't know if that still works when thawed.  I'd be concerned about water separating out of the ground chickpeas during the freeze-and-thaw cycle.  If you do this anyway, and the batter doesn't want to hold together afterwards, I suggest adding a little dry chickpea flour to it.