You could try the open lock scroll from arhu's desk ... don't know if this works.
AFAIK scrolls only remove glowing purple magical locks and has nothing to do with "regular" locked chests. I tried to use scroll in black cove on level 20 locked chest with no success before. But I will try it on Baccus chest though. Just to be sure.
An alternate way would be to go into lucella forest and try to destroy the goblin totem for the bloodstone - don't know if you can avoid exploration XP on this route. If this works you don't need to go after evelyn for your fifth stone.
Not viable. You get enormous amount of exploration XP in the forest (as 3-rd level character). I will be level 4-5th by the time I reach goblin camp.
Thanks for the advise anyway.