EoH: It is Khnum Khfw.
SC: Whether it is xfw or xwf is immaterial. It is still not the same as xwfw. 'Khufu' is not the same as Khnum-Khfu.
What vowels were used in these names i.e. xwfw and xfw?
You do not know which vowels were used so that means it is entirely possible that xwfw was, for example, spoken as xIwOfEw whilst xfw might have been pronounced entrely different: AxUfIwE.
The point is that they can appear very similar but have totally different vowel sounds thus making them completely different names. We just don't know any or how many vowels were used in these 'names'.
And you still did not repsond to my point about 'Suphis' transliterating to Khufu--where is the pre-transliteration of Khnum-Khuf (or Khfu) in the historical record?