It isn't that bad, like the Robomi event, you just have to roll Sig's weapon from that pool of rewards. You will eventually get her if you keep emptying the pool. You could potentially roll her in your very first roll....Usually these do not have much to roll from either.
If you have time to use up all your AP and EP from natural regeneration it's basically impossible to not empty the first box or even two. She will be pretty much as guaranteed as trust characters. Only will need more time to get. Maybe the will add a follow up quests netting some extra tokens like with Robomi as well.
By the way, dark fish summon is from this or some other event?