I got mine without sacrificing the 5* sweeties!
Way. It wouldn't have been worth the trade off.
This is tip for the people who struggle with the mission. Check your inventory for christmas event summon ticket 3-5 to earn needed childs for onyx, and you won't need to destroy your 5 stars for the quest.
Thanks! I used some of them, but forgot about them, as I started saving summons tickets for Planet Party. Doesn't make sense to save event specific summons, for sure!