Ellana's answers will be that she was taking part in the mage training sessions and taking what she learned there to Sina, since there were worries about how Sina's shard would react in a big group (and personally, Ellana thought Sina might not want to be in a big group setting). At the start, they were focusing on Dalish demon-resisting techniques, so really just a refresher course for Sina. She hadn't left Sina with any instructions on magic she should be practicing on her own, so she has no idea what Sina was doing at the time. Ellana also has confidence in Sina as a mage, because Sina was raised as a First. However, Ellana is concerned about this shard and how it may throw all that out the window.

Ellana does agree that a Circle-trained mage would be better, because they have had access to a lot more literature on forms of magic. ICly, Ellana doesn't know who has been studying the shards, but she'll ask around! OOCly, I have no idea either, lol.