I've read the first chapter.
...I can has clue about what's going on nao pls?
This world is weird.
And no, little girl. She isn't there to steal the Grail. She's there to
rescue the child. It isn't Miyu's fault she was made inseparable from your world's grail.
Still missing: two Kaleidosticks, one dark-skinned twin with the Archer card in her whose existance probably remains in great peril, one magical girl/Holy Grail conduit/best friend, and at least two mages. Not worried about the Gil kid thing both because all the spoiler pictures show him in them, and because frankly I don't like him and I don't want him near any of my girls or taking up their screentime.