Are there readings exclusive used only for people name?
So I wonder, are there readings exclusive for a name without any preceding usage (meaningless/not used in historical names)?


I think it is very unlikely to have a reading in a name with no meaning at all.

Take a look at the character 樂

The pinyin of 樂 in 快樂 (happy) is /le4/ ; in 音樂 (music) and surname, is /yue4/ 

Which mean when reading 樂 in a surname, it is different from the 樂 in 快樂, but is the same as the 樂 in 音樂.

As a surname 樂 also has a second pinyin /yao4/. (It means 'to love; be fond of; to delight in') 樂進 /yao4  jin4/ is an example.

Although the /yao4/ pinyin can only be seen in classical text nowadays. For example:'仁者樂山，智者樂水', we can't say 樂/yao4/ in 樂進 has no preceding usage.