Thanks a lot for your work! But unfortunately I couldn't get the scenes for Jeanne even after following your instructions unless I did something wrong. (which is likely)
What I did was delete the ジャンヌ ・ダルク folder first in kamihime_SSR and pasted in the ジャンヌ・ダルク[れじぇくろ] you provided and also replaced the config.ini in game\dmm. I then ran 3_write_config and opened the player afterwards but couldn't find her so I then opened 0_download_json, 1_download_assets, 2_build_rpy and then 3_write_config again and still couldn't find her.
You'll have to edit config.ini every time you run 3_write_config so that the kamihime's info is different from the soul's info. Open config.ini in a text editor (I use Notepad++) and search for 'ジャンヌ・ダルク' and make sure that the soul's info has 'name = ジャンヌ・ダルク' and 'type = soul'. For the kamihime, make sure the entry name (the one in brackets above title_1) is '[ジャンヌ・ダルク(れじぇくろ)]' (needs to match the raw_scenario folder name), 'name = ジャンヌ・ダルク(れじぇくろ)', and 'type = kamihime_SSR'. The same logic applies to the two versions of Diabolos with identical names. If you are unwilling or unable to edit config.ini after every usage of 3_write_config, then you'll have to wait for someone to update 3_write_config so that it can deal with matching names for characters in different categories (souls, eidolons, R, SR, and SSR kamihime).
I'll include the JSON files for the DMM soul skin Mordred [Flower Garment on Head] here. The 3 previous DMM soul skins are on post #619.
Edit 1: I've included comparison images for DMM's Jeanne d'Arc (Legeclo), DMM's Diabolos (SR Kamihime), and Nutaku's Diabolos (SR Eidolon) config.ini entries. The left side is the appearance after running 3_write_config and the right side is after the manual edits are applied.