Headscratchers / Niko and the Sword of Light

• Lyra says that she hasn't walked in about 700 years...However, wasn't she walking when she went to tell everyone about Niko's awakening, back in her castle? What's the difference between walking there and trying to walk outside of it?
• I understand that they thought Niko wasn't ready, but wouldn't it have been best to bring him along to the volcano with Aura? If she fails again, Lyra can't take the shard and fly away like she could before, and the only ones who can make it into a weapon are the Champions. Why not have Niko tag along, so that in case Aura fails, he can take up the weapon and at least attempt to take on Nar Est?
• How come sometimes when Niko (or Aura) drops or loses the Sword/Bow of Light, it turns back into a shard, whereas other times it just loses its glow?
• During the first season, the first few episodes are spent searching for a place where Niko can live and train without being threatened by Nar Est’s creatures. So why didn’t Lyra take him back to the Temple of Champions? It must be pretty safe, or else it wouldn’t have lasted the 768 years since it was built.