What is the basis of your understanding that Midyan is around Kuwait? My rudimentary understanding placed them near Moav. It would have been quite some distance for there to be an abundance of Midyan women right near where the Yidden were when near Moav, Sichon and Og and they would have needed to travel there to wage war with them as described in the pasuk.
My basis is the possuk פתורה אשר על הנהר ארץ בני עמו which places Midyan (ארץ בני עמו) on the bank of נהר פרת. (see Rashi and Unkelos
here and
here)
I also wonder if the geography might have changed with the events described in שירת הבאר. Is it possible that the gulf of Eilat/Aqaba didn't exist at the time, and was only created by the seismological event described in שירת הבאר?