If you stick with Shar, then it's her that continues to grant her powers. Light domain doesn't fit until the moment Shar abandons her (and then trickery doesn't fit). Shadowheart was created with the respec function in mind.
Sure.
If you completely ignore the part where after Shar abandons her and she retains her powers Shadowheart says "I guess we know who was granting my powers all along"
Suggesting that it's not the goddesses passing over responsibility for Shadowhearts power, but it's always been Selune.
