Are rewards from the clan chest proportional to what you have put in?
Clan chest rewards are totally random!
The only need for getting it is to contribute at least one crown to the chest.
About inactive members of your clan, if they didn't bring 1 crown to the chest, they won't earn anything!
Let's say you got 10/10 Chest, you will earn about 270 cards, 27 Rares & 2 Epics (chance for legendary) according to your current arena.