Why does the Torah insert the second "ve'ha'Basar"?
Rashi: It comes to permit Basar of a limb of Kodshei Kodshim, part of which left the Azarah, or of that of Kodshim Kalim, part of which left Yerushalayim - to permit the part that remained inside to be eaten. 1
Although this is not the case regarding Tum'ah (See Ba'al ha'Turim).
And what is the last part of the Pasuk ("ve'ha'Basar, Kol Tahor Yochal Basar") coming to teach us?
Rashi #1: It is coming to teach us that not only the owner, but anyone who is Tahor, may eat the Shelamim.
Rashi #2: That although the Basar of a Chatas and an Asham that leave the precincts of the Azarah may not be eaten, 1 the Basar of a Shelamim may be eaten anywhere in Yerushalayim.