What is the significance of the word "Re'u"?
Torah Temimah (citing B'rachos, 55a): We learn from here that before appointing a communal leader one must obtain their consent.
Who was Chur?
Rashi: He was the son of Miriam. 1
See Sifsei Chachamim. It is not clear however, as to why Rashi did not make the same comment in Shemos 31:2? Others therefore explain that Hashem was pointing out to the people that He chose Betzalel to build the Mishkan to atone for the death of Chur, whom the people murdered by the Eigel (See Da'as Zekeinim mi'Ba'alei Tosfos).