Shelo yeestakel memakom erva, or kedei shelo yeenok bemokom teenofet- What is the nafkah minah and what is the message? similar to moshe being yonek only from an eevrei?
Why the need for twoi pesukim (bottom of amud a and beginning of amud b hen yakteleini lo ayacel and yeshayhu??
It seems to me that 'she'Lo Yistakel be'Makom Ervah' is a matter concerning the spirituality of the baby, whereas 'she'Lo Yinak mi'Makom ha'Tinofes' concerns his physicality. The former clearly spares him from bad thoughts, the latter, from "bal Teshaktzu" (doing something disgusting).
As for the two Pesukim that you refer to at the foot of the Amud and just over the page, I think that Chizkiyahu cited the tradition that he had from his grandfather David (which was said with reference to an incident which occurred, as quoted by Rashi). He preferred to cite that Pasuk, precisely because it came from his illustrious grandfather, even though the circumstances here were very different. So the Gemara cites a second Pasuk, based on Rebbi Chanan's statement, which is more appropriate for the case at hand.
Kol Tuv,
Eliezer Chrysler