1)
What is the intent of "Yosef Hashem Aleichem"?
1.
Radak #1: It is a Nevu'ah.
2.
Radak #2: It is a Tefilah, like Yevarech.
3.
Malbim: Since via the big, also the small are blessed, Hashem needs to give a bigger Brachah to the Gedolim, due to their higher level. However, also the bigger Brachah, the smaller receive via the bigger.
2)
Why does it say "v'Al Beneichem"?
1.
Radak: This is like it says "ha'Ketanim Im ha'Gedolim" (13).
2.
Malbim: Via the big, also the small are blessed. Hashem constantly needs to increase Brachah on the Gedolim, and it includes the Ketanim.
