Costume requirements
Yuela
Earth -- Ch1+, Aht Lv6
Dark -- Ch3+, Sharty Lv12
Fire -- Ch4+, Clear Quest 59 (given by Tian in chapter. Requires Saerav)
Omni -- Ch6+, Aht Lv14, Suina Lv12, Saerav Lv18, Crayl Lv18
Light -- Ch7+, Elizasleyn joined
Gothic -- NG+
Cameo -- NG+ and Gold Disk Append

Emelita
Water -- Ch1+, Suina Lv7
Omni -- Ch3+, Melodiana joined
Light -- Ch5-6, Clear Quest 75 (Melodiana lv 15, Wil lv 22)
Earth -- Crayanne Lv 28
Wind -- Ch8, Gaptahl joined
Gothic -- NG+
Cameo -- NG+ and Gold Disk Append

Serawi
Wind -- Ch2+, Crayl joined
Water -- Ch3+, Suina Lv 15, Quest 5 cleared (mandatory ch3 quest)
Dark -- Ch5+, Melodiana Lv25, Sharty Lv25
Fire -- Ch7+, Clear Fox Shrine dungeon (Clear Kohakuren quests, then Saerav events in Ch7 to open it)
Omni -- Ch7*, All Yuichiri, Gaptahl, and Paraskevas events cleared, Crayanne Lv 28, Kohakuren Lv35
Gothic -- NG+
Cameo -- NG+ and Gold Disk Append

*It's awarded in chapter 8, but some of these quests have portions that need to be done by chapter 7

Gold Disk Append<<<< i cant get it i have finish the game twices does anyone have the image of the item? that will be a great help! srry for bad english

It should automatically unlock once you finish the game. It should be in the clothes section waiting to be made.

hmm in my clothes section from what i saw for yuera gothic >> is the green colour costume with a pink hair on it. Earth >> beast costume .
Dark>>> gt horns on it. Fire >>> Red. Omini >>> Holding teddybear . Light >>>> White + abit of Blue. i dont see any cameo receipe. i will post a screenshot later

You have the armor, It doesn't actually say the name as cameo. Yuela's cameo clothing is God Slayer Armor, its the green/white armor and she got pink hair. Her gothic armor is the Gothic Doll Armor where shes got blonde hair and holding a teddy. For emilita her cameo is Little Devil Robe, and Serawi's is Elf Princess Tunic.

oh i see thx