There are exceptions from the general rule of Elemental Dignities. The first one are the Aces, which becomes clear when you look at the Sephirah associated to them: Kether.
The Aces are not exactly the element of their suit but the source of it, they are the first seeds, responding to Yechidah which in terms of the elements is equivalent to the Spirit or the Aether.
In the Aces the element is only just born, not in the sense of a weak baby but rather in a powerful eruption. Aces are strong cards and not even the most hostile surrounding will weaken the strength of their appearance. One might argue that an 'explosion' of a Fire spark might not live very long when born into a sea of Water but this is not what the Aces are supposed to, anyway. They are always just the first stir up, it's up to other cards to render the power into a lasting presence.
Actually, both the Magician and the Fool are attributed to Air while the High Priestess is attributed to Water - and it might be perfectly okay to simply go with these connections.
On the other hand, these three Major cards are often seen as exceptions from the rule for the same reason as the Aces: their connection to Kether. If you look at the Tree of Life and watch the Paths coming from Kether, you will find that the Fool goes from Kether to Chokmah, the Magician from Kether to Binah and the High Priestess takes the long way down from Kether to Tiphareth.
It is hard to say which way is 'right' and as so often in Tarot there is a bit of both. I usually leave it up to the cards to decide - if for example the High Priestess is accompanied by another Water trump and several Minor Water cards I definitely won't ignore her Watery side.
In the Tree of Life both the Tens and the Princesses are associated with Malkuth. While Malkuth does respond to Nefesh and Assiah and belongs to Earth it also combines all the elements within it, as is explained in the article. For this reason we cannot see the Tens and the Princesses as 'pure Earth' since Malkuth is pretty far away from this, as well.
This does not mean, however, to simply exclude these cards from the rules altogether. The Elemental Dignities still apply, only in a more subtle, not quite so determined manner.