Seeing as the Torah in Emor Vayikra, 21:1, confines the prohibition against becoming Tamei Meis (with its stringencies) to Kohanim, why here, does it include Zarim in the prohibition against Tum'as Neveilah, which is more lenient than Tum'as Meis?
Rashi: Because the Pasuk is referring to Yom-Tov, when everybody is obligated to be Metaher oneself.
Da'as Zekenim and Rosh: Because the Torah is forbidding touching them in order to eat them. The Torah repeats the Isur 1 to eat using an expression of touching. 2
Hadar Zekenim: The Torah regularly changes the expression when repeating something. If one receives Malkos for touching, all the more so for eating! (Beis-Din cannot give Malkos based on a Kal va'Chomer! Besides, it is possible to eat without touching - Refer to Vayikra 11:40:2:1 and note. PF). Rav told Rav Kahana [it is preferable to] flay a Neveilah [than to take Tzedakah] (What is the proof from there? One can flay with gloves or some other covering on his hands, and not touch the Neveilah! Presumably, if one may not touch a Neveilah, all the more so one may not move it, which is Metamei even more (also his clothes). Or, perhaps one cannot flay properly with covered hands - in those times, when they did not have thin plastic gloves ? PF).
Like "be'Chol Kodesh Lo Siga ve'el ha'Mikdash Lo Savo" (Vayikra 12:4). The answer seems to be two answers: 1. The Pasuk is talking about touching in order to eat; 2. 'Touching' in this Pasuk really means eating'?
The Torah wrote an explicit La'av for animals with one Siman Taharah. What is the source for a prohibition againsgt km,n animals with no Siman Taharah?
Refer to Vayikra 11:3:151:1 & 2 and notes.