They're also Kael'thas. :)

"and when are we going to see those tumbled, huh?!"

Blood Elves can say that those male statues are from Anaesterian Sunstrider, father of Kael'thas. Many said that both are very similar in appearance, so why not make that excuse?

About the female statues, i think is more for the looks rather than lore, like gnomes or cherubs in our gardens and fountains.

Hard to say. There are two High Elven statues outside Silvermoon City, both with inscriptions. Could be one of them...

On the other hand, could be an High Elven woman of the last 6000+ years. High Elven history is largely unknown between the founding of Quel'Thelas and their appearance in Warcraft 2. Only a few definitive things are known, such as their teaching Magic to Humans, and their trade with the Wildhammers.

In particular, their leadership over the years goes:
Dath'Remar Sunstrider

Anasterian Sunstrider
Kael'thas Sunstrider
Lor'themar Theron (at the moment).

But as I say, too big a gap in High Elven history.

It is feasible that there was a proper Queen involved at some point, and the statues could be her.

There was a queen; Queen Azshara.
from wowwiki
"Queen Azshara, the Empress of Nazjatar, was the beloved ruler of the kaldorei ten thousand years ago and the current ruler of the monstrous naga. Entrancingly beautiful and beloved by her people, Azshara began a descent into madness when she was corrupted by the Dark Titan Sargeras, master of the Burning Legion. After her defeat at the hands of Malfurion Stormrage, and the Great Sundering that sent her and much of her Highborne into the depths of the sea, Azshara was transformed into the Empress of Nazjatar — progenitor of the serpentine naga. Azshara is the greatest mortal mage ever to live. In fact she may no longer be mortal."