I placed all my corrections between two (), comment if something is not clear.
Is (to) set a date and find the location.
out the menu, (as well as the) entertainment.
input from other(s) and (assign) them tasks to (complete).
mail the invites out(no s).
or event (got underway, I would)
the guests(s) (were) having a good time.
I would say B, because fabric clarifies what yards is. Hopefully this helps and good luck!!!