Okay, if Raven isn't going to contribute more than 300 to the Eternal Wand, I'm not sure we can afford it. To simplify the math, I'm going to reassign everything that Stulgar and Siobhan bought.
So if Siobhan spends her entire money on shares of the Eternal Wands
(), that would buy her 410 (the whole CLW Eternal Wand) + 1230 (her share and Stulgar's share of the CMW Wand) + 260 (not enough to pick up Raven's deficiency on Raven's share of the CMW Wand, but almost). If Lily then pays her 615 share of the CMW Wand, that leaves Stulgar to pay 49 gp (the rest of Raven's share that Siobhan couldn't pick up) + buy the Haversack completely himself.
Okay, I think we can afford that. Although, as a player, it makes me rather unhappy because I have a 4th level character who doesn't own a relevant piece of equipment that isn't starting equipment or a healing wand, but I have no recourse in-character as Siobhan (another character might, for example, charge money for wand uses to party members who ran out to buy themselves new stuff and made the healer pay for the wands). I guess this is the trouble with living worlds though--in a normal game, the party always ponies up to split the cost of wands completely evenly because they know they're going to stick together, but the shifting nature of Living Worlds makes that uncertain.