that的先行项是什么

艾登蒂基特相貌拼图（依据目击者描述拼制出人的面部像，尤指警方要捉拿的人）
a set of drawings of different features that can be put together to form the face of a person,

是different features还是drawings of different features？我感觉是different features。

你从逻辑剖析，放在一块拼成人脸的a set of drawings, 还是features？

显然是a set of drawings, 只是drawings又有定语修饰而已。所以that的先行词为a set of drawings of different features这个名词词组，而不是features。