1)
Why is "v'Es Yom" repeated?
1.
Vilna Gaon (based on Megilah 5b): [Megilas Ta'anis] is needed to forbid this [Kerachim, to fast or eulogize] on this (the 14th in, even though it is not their day of Simchah) and this (open cities) on this (the 15th 1 ).
1
He explains that "v'Es Yom" separates the 14th from the 15th, to forbid each place only on its day. Due to a later enactment of Megilas Ta'anis, both places are forbidden on both days. (PF)