What is the reason for the specific items listed in Pirkei Avot 5:6 being created just before Shabbat?

Question

Pirkei Avot chapter 5, mishnah 6 says:

Ten things were created at twilight of Shabbat eve. These are: the mouth of the earth [that swallowed Korach]; the mouth of [Miriam's] well; the mouth of [Balaam's] ass; the rainbow; the manna; [Moses'] staff; the shamir; the writing, the inscription and the tablets [of the Ten Commandments]. Some say also the burial place of Moses and the ram of our father Abraham. And some say also the spirits of destruction as well as the original tongs, for tongs are made with tongs.

Three related questions:

Why were these specific items chosen to be created just before Shabbat? Why were these items created specifically before Shabbat as opposed to some other time? Could the reason these items were chosen be that all of them (except the tongs) were "one time" use?

Answer 1

The Maharal says that the twilight period before the first Shabbos has a dual quality. It is still Friday, so it is still a day of creation, but it is Shabbos, a day above creation. So the things created at that time are of a miraculous and not of the natural order, but are still creations of G-d.

The Midrash Shmuel says that since Adam sinned before the end of Friday, these things were created after that to counteract the darkness created by that sin.

The thing which doesn't really belong on that list, according to those explanations, is tongs. They aren't exceptionally miraculous (you could make the first pair by pouring into a mold). The Lubavitcher Rebbe explains that the idea of tongs is they are a facilitator to a meaningful act. By Hashem creating those tongs Himself, He granted meaning even to those parts of life that seem to be only means to a holy end. This ability is something granted by the twilight of the first Friday.

(Taken from the Kehot Pirkei Avot)