Fashionista, one in exotic plumes, makes sudden advances (7,5)

'sudden advances' is the definition.
I know nothing about this answer so I cannot tell whether this works.

'fashionista one in exotic plumes' is the wordplay.
'fashionista' becomes 'quant' (I can't justify this - if you can you should believe this answer much more).
'one' becomes 'a' (a thing is one thing).
'in' indicates putting letters inside.
'exotic' is an anagram indicator (an unusual form of the letters).
'plumes' with letters rearranged gives 'umleps'.
'a' put inside 'umleps' is 'umleaps'.
'quant'+'umleaps'='QUANTUM LEAPS'

'makes' acts as a link.

Can you help me to learn more?