Black Panther and the beginning of the War

Black Panther is the final MCU movie before the Infinity War, and fans are asking themselves why Kevin Feige said that the movie would mark the beginning of Thanos' war. Of course, Wakanda is one of the most advanced countries in the MCU, and it’s also the richest in Vibranium (the metal that’s also the source of its technological advances). So it would make sense for the Mad Titan to strike here first.
But there is another possibility. In total, we know the locations of five Infinity Stones "“ the Tesseract, or Space Stone (guarded in Asgard); the Aether, or Reality Stone (in the Collector's possession); the Orb, or Power Stone (guarded by the Nova Corps on Xandar); the Mind Stone (etched on Vision's forehead); and the Eye of Agamotto, or the Time Stone (used by Doctor Strange). And there is still the Soul Stone. So could Thanos have two reasons for attacking Wakanda first?
Among all of the rumors on this list, this is the thinnest "“ but it should be taken into consideration.
Of course, the Soul Stone could appear in another movie"¦
