There are some family names which are pronounced quite differently compared to normal usage. For example:

* 华：usually: hua2, family name: hua4
* 仇：usually: chou2, family name: qiu2
* 单：usually: dan1, family name: shan4
* 任：usually: ren4, family name: ren2
* 纪：usually: ji4, family name: ji3
* 解: usually: jie3, family name: xie4
* 查：usually: cha2, family name: zha1
* 区：usually: qu1, family name: ou1
* 尉迟：usually: wei4, chi2, family name: yu4 chi2
* 万俟：usually: wan4, si4, family name: mo4 qi2

Some of the pronunciations above are indeed exclusively to family names, but they are pronounced so with a reason. For example, however, I believe these pronunciation all have historical reasons, either a place, or 四声别义, or another character.

Besides, I think 名乗り(nanori) in Japanese also have a reason and not exclusively for names without other meaning. For example, 希 in female names reads nozomi, it's actually 訓読み(kunyomi) of 望, which has a similar meaning as 希. And ii is the classic form (雅語) of meshi for 飯. Therefore, the basis where your extension based on is also unstable.