the only problems with that would be the facts that:
1) individual strength would not be an issue and this is a factor since each character's strength changes differently over time, changing how their encumbrance is affected for the inventory.
2) the summoning dolls, whose inventory and encumbrance and strength only count when they are in play, would not exactly fit well with the combined inventory idea. if the summoning doll was encumbered then as soon as it popped into play, everyone automatically becomes encumbered or somehow the inventory it has is redistributed amongst everyone else until such time as it goes away, to prevent encumbrance of the doll.
either way its an all or none situation. either no one is encumbered or everyone is, and this isn't feasible.
