ACTUALLY, the blunt facts of the matter are there is no "OFFICIAL" Valen Mod and anyone is free to use the Valen character in their own mod......
If you'd like to get into the legal and technical side of it, by all means, but then again if you did that, everyone out in the modding community could be up and sued without question for altering and editing a copy written program. Valen is a character created by Black Isle, so there is no official Valen outside the one that comes to your party and offers the chance to go to the graveyard. In all reality -no one- has the right to alter or change anything within the game. It doesn't even matter if you went out to the store and bought your copy of BG2. You just own the discs and whatever else came in the box, you have no rights to any of the data stored within it, nor any right to alter it.
I'm a strong supporter of modding, but if you want to dig down to the facts that's more then fine with me.
Now then, let's take it a bit further. Weimer made his own version of Valen, and altered her into what she is within this mod. He never really had the "rights" to do it, but did so any ways for his own enjoyment, or what not. This would then be called an 'official Weimer alteration'. Now Thorium is altering a character yet again, he's not Black Isle, nor is he Weimer, and lastly he still doesn't have the 'rights' to do it. Thorium's creation will no longer be Weimer's mod, but it will be Thorium's with the basis of Black Isle and Weimer's work. So again, No. Weimer's Valen is, as far as we all know, no longer being worked on by Weimer, nor will he be adding a romance unless he returns to the work, permission was given to Thorium to alter -Weimer's-Valen, but it is -not- of Weimer's creation, nor of Black Isle. So once more, for good measure, No.