Welcome Tigre. :) I just saw the edit. It is heaps clearer now.

Also....

Thanks for the submission Limey. 

I like both character designs a lot, but I have 2 concerns:

1) Bjorn's specialization is too similar to Seira's. She is able to use metal to create and enhance weapons. Though only limited to metal. There is also a Chrono with a weapon altering ability but it covers a larger range of weapons and the ability is not restricted to metal. Maybe you could consider a different alch-specs for Bjorn? 

Some suggestions I thought of (keeping to the smithing theme): 
[s]Weapon Augmentation (literally strengthening and weakening weapons)[/s] - sorry this ability is not allowed. Just clarified it. =(
Super Human Strength (literally smashes through the ground)
Fire Manipulation
Fire Endowment (charges a weapon with elemental energy)
Weakness Exploitation/Shattering

Though to be honest... I was thinking possibly both siblings could have different forms of electric control e.g. bioelectric control, spark generation, etc. :) I mean divide and conquer!

2) I am not sure if the siblings can be fifth generation Asylums due to the mortality rates in AMRO. I think you could say that they either come from a long line of alchemists a la Don and Fiora, their parents were Alchemists like Lina or their parents were rogues. Alternatively you could avoid that altogether and say the kids were raised in the AMRO orphanage.