That's cute, a "Sunday name". We don't use this phrase in the states, I like it. Basically I agree with what eyeofh said, except that the different forms of a name are modern inventions, which imho, are attempts to reconcile different glyphs with the established dogma, and all this came about AFTER Vyse. What transpired BEFORE Vyse is what egyptologists used as the foundation for their Khufu.
"Suphis" only appears in Africanus (Manetho) 160-240 a.d. (dates are uncertain). There it suddenly pops up out of nowhere as being the king who built the great pyramid. I have not found the name anywhere else.
It was Wilkinson who made the leap from the now famous cartouche to Suphis. He wrote:
Among these we evidently perceive Suphis, or as the hieroglyphics write it, Shofo, or Khof, a name easily converted into Suphis or Cheops, by adding s, the Greek termination.
And that's all there is to it, just add 's' !! Notice how he uses the word "perceive", it's a clever way of saying 'assume'. In the true egyptologist form, you are free to change vowels and to add or subtract consonants as you see fit. I think your analysis of different hieroglyphs carry more logic than what Wilkinson wrote. And I seriously doubt that Wilkinson was an expert on ancient Greek.
Egyptologists have a most irritating habit of simply writing off the authors before Africanus as just being "wrong", without saying why. Probably because it was easy (lazy) to use Manetho's dynasties to build a time line that they could build 'expertise' on. So they placed more value in Africanus than in the older authors who wrote of the builder of the great pyramid as being.......
HERODOTUS - 4th century b.c. "Cheops"
STRABO - 1st century b.c. "Chembres / Chembes"
DIODORUS - 1st century b.c. "Chemmis"
I find "Chemmis" the most interesting; the name has a fascinating history and there might be a clue in it.
But I think I shall start a rumor about "Suphis". Africanus was a Christian, in the years of secret cults and religious changes. According to Cory's 'Ancient Fragments', his original text has Σουφις (greek) which, according to Google, translates to "Soufis". Now if you drop the 's' on the end, it comes out "Sufi". The mystical Sufism ?? Sounds as good as what Wilkinson and some alt authors have written. And using logic as flimsy as Wilkinson's, I could build a whole theory around it.