No, you are quite correct.

But that's beside the point. The point is that a fraction of the group "the Aiel" will be saved, but the rest will be destroyed. The way you choose to define "the Aiel" for the sake of this prophecy doesn't matter unless it can lead to both those end results.

Aviendha's vision is not possible, because regardless of what defines that saved fraction of the Aiel, the other part of that fraction was not destroyed. The prophecy predicts both.

If you choose to define "the Aiel" in a way other than the accepted use of the term as referring to the tribal people from the Aiel Waste who share a similar culture and history, then you may attempt to do so, but it needs to be able to fulfill those two end results. For example, it must be a group of people preexisting at the time of Rand's actions as the Dragon Reborn, elsewise there is no remnant to save nor any portion to destroy, as it is impossible to divide by zero, nor to save people who don't exist, nor to destroy people who don't exist.

So for the sake of clarity, please answer these two questions:

1: Do you agree that the Rhuidean Prophecy states that He Who Comes With The Dawn will destroy "the Aiel" except for a remnant of a remnant whom he shall save?

2: How do you define "the Aiel"?