Regarding the vocalization of "tsafnat" in the phrase "tsafnat pa'neah," I've given my opinion that the vowel of the tsade is kamats gadol and the vowel of the feh is sheva (the one called "sheva medium" in old grammars, resulting from the reduction of a vowel, not pronounced but still causing a following bet to become vet, etc.)
I've been asked how the sheva can be "silent" if it follows an open syllable containing a long vowel. The example of "toldot," covered in HCM, is not, apparently, convincingly similar. I worried for a long time trying to think of comparable examples with kamats gadol, then noticed a plethora of them in the verbal system--think halkhah, halkhu. If you argue that "tsafnat" is not a verb, I'll just have to ask you, what is it then? A noun in semikhut? Like "toldot," then? The phrase has been puzzled over by many scholars. Gesenius, for example, says the whole phrase is mangled Egyptian (appropriate for a title granted to Joseph in his Egyptian period), which ought to account for any vocalic peculiarities. Our mentor, Paul Maher, has commented: "HCM was not written to be a serious grammar but to describe what one could observe in the files and to encourage similar results in various places." In dealing with oddball phrases like "tsafnat pa'neah," consistency should be our goal, though that may be a poor second if we fail to agree on "correctness." Joan