Are characters divided into meaning part and phonetic part, with no overlapping?
According to 六書 : six categories of Chinese Characters (象形,指事,形聲,會意,轉注,假借)

四、形聲 phonogram
a. [meaning + phonic] combination character (with original forms of both components intact)
b. 形聲 (Phonogram) express both meaning and phonic. Different from 會意 (associative compounds) which can only express meaning.

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三、會意 (associative compounds)：
c. associative compounds including phonic component：
Example: '婢' = '女'(female)+ '卑'(humble); '卑' is also the phonic component

The character 婢 belong to one type of 會意字, which both components contribute meanings to the character, and one of the components is also the phonic component.
My conclusion is, phonic part in 形聲字 (Phonogram) may or may not contribute meaning. For example: 江(river) =(river + 工 phonic); 聞 (listen) = (ear on the door with 門 phonic)
If one of the two meaningful parts in  會意字 (associative compounds) does contribute phonic element to the character, then it is a type c 會意字='會意形聲字'(associative compounds including phonic component)