The six methods of character creation are mutually reinforcing not exclusive and are in modernity not the only ways to classify or form Chinese characters. For examples: ideophonetic characters combine a phonetic component with a symbol, whereas picto-semantic characters combine an image and an symbol. These might respectively be seen as variants of picto-phonetic and ideographic characters. Here’s a translation of a Chinese language texts on character creation:
用某个字做读音符号组成的新字叫做意音字 using some character’s phonetic component to form a new character is called making an ideophonetic character. (sound component + idea component)
用字形的字意组成新字的叫做形意字 Characters using the pictographic and semantic component of one character to create a new character are called picto-semantic characters.
Surprisingly, baidu as well as google got this one a bit wrong. Unsurprisingly, baidu was better than google at machine translating this somewhat complex and obscure text.