[Joly]

Ryukishi07 does supervise the artist's outlines for the manga, so I don't think much of the content from the manga should be ignored. And if the artists do want to contribute their own personal element to the story, they had to go over it with Ryukishi07 himself for approval. At least, that's the impression I got from reading the Ryukishi07 and Karin Suzuragi (Onikakushi-hen, Tsumihoroboshi-hen, Matsuribayashi-hen manga artist) interview on Yen Plus.

Spoiler for Here's an excerpt of some of it...:

Yen Plus: How do you divide up the work on the manga?

Ryukishi07: Suzuragi uses my original game to outline the story and draw the name (storyboard), and I supervise. Suzuragi is kind enough to love the original very much, so her outlines and name are wonderful! As the creator, there is no other artist that I can feel so at ease about leaving things in her hands.

Suzuragi: I play the original game, and from there I create the script and panel layout for the manga.

Yen Plus: Suzuragi, your art style is different from Ryukishi07's original designs for the Higurashi games. How much freedom did you have in redesigning the characters for the manga?

Ryukishi07: As long as Suzuragi brought the image of the original work to life, I had no problems with her drawing it freely. At any rate, my drawings are terrible (sweat drop). I think the characters are happy to have Suzuragi draw them so adorably too.

Suzuragi: Oh, that's very kind of you, but my aim is to match the designs of the original.

(And here's a small part from Suzuragi's individual interview.)

Yen Plus: What do you feel is the biggest personal element that you have brought to the Higurashi manga? Are there any ideas or images that you personally contributed to the story?

Suzuragi: They very kindly used my design suggestions for Aiko and Rena's father.