As far as I have seen, Soulbound places no restrictions on duardin learning the spellcasting talent (excepting The Ethersea and The High Peaks). Does Age of Sigmar lore feature any examples of spellcasting duardin?
Were all of the souls selected to be Stormcast Eternals originally humans? Were any of them originally aelves or duardin (sylvaneth seem extremely unlikely)? If they were originally non-human, would their reforged body still cosmetically resemble their original species (but bigger/taller)?
Do aelves and/or duardin in the Free Cities worship Sigmar? There do not appear to be any species-based restrictions on the Blessed talent, or the god that anyone with Blessed can select. Does this mean that duardin with Blessed (Khaine), aelves with Blessed (Sigmar), humans with Blessed (Teclis), and sylvaneth with Blessed (Grimnir) are all possible? For that matter, can Stormcast Eternals become Blessed of any god other than Sigmar? Does Age of Sgmar lore feature any examples of cross-species priests/Blessed?