1)
Is "Ayin" part of Eretz Yisrael or not?
1.
Rashi: Since the Torah is defining the eastern border, "east of Ayin" indicates that Ayin is in Eretz Yisrael. 1
1
Rashi: And the same applies to Yam Kineret where the Torah inserts the word "Keidmah."
2)
What are the connotations of "Veyarad ha'Gevul"?
1.
Rashi: Whenever the border runs from north to south, the term "Veyarad" is applicable.