1)
What is the connection between "Ve'es ha'Aretz ha'Zos Yarashnu .... " and "me'Aro'er asher al Nachal Arnon"?
1.
Rashi: They refer to two different things: "Ve'es ha'Aretz ha'Zos Yarashnu .... " refers to "mi'Nachal Arnon ve'ad Har Chermon Yarashnu ba'Eis ha'Hi", whereas "me'Aro'er asher al Nachal Arnon" refers to "Nasati la'Reuveni ve'la'Gadi" (that follows it).
2.
Ramban: It is as if the Torah had inserted the word "asher", and reads "ve'es ha'Aretz ha'Hi asher Yarashnu ... Nasati la'Re'uveini ... ".
