What is the significance of the triple blessing
Ramban #2: It refers to the judges who perform Mishpat, inasmuch as Hashem will cause the families whom they have found guilty to love them, no harm will befall them (the judges) following their harsh judgment ("u'Veirach'cha") and they will not decrease on account of the death of the sinners ("v'Hirbecha")
What is the translation of "Shegar Alafecha"?
Rashi: 'The babies of your cattle'
See Peirush Yonasan.
What are "Ashteros Tzonecha"?
Rashi #2 (citing Targum Onkelos) and Targum Yonasan: 'Your flocks of sheep'.
Rashi #3 (28:4, from Chulin 64b): They are called "Ashtaros" because they make their owners rich ('Ma'ashiros Ba'aleihen) and strengthen them