What are the differences between the Echo and having Hydaelyn's Blessing? [Spoilers?]

[Rannie]

I have to wonder, did Minfilia gain her Echo in that crypt? Going by the Tales from the Calamity, she seemed to gain the Blessing of Light a few years after that.

Going by how the echo is always linked with that meteor shower and it happened that day (the real meteor shower that even Thancred saw) in the crypt, I would have to say most likely so, though it could have been more at the moment when you had triggered the echo within the echo and caused it to awaken in her thus causing the meteor shower >.<