If Quaithe is using a glass candle to perform her magics, the I'd say it is just another version of the third eye.
Or Ghost is another version of a glass candle... if we're talking inversions. A magical creature and a magical object that must be activated.
Yeah, Ghost was the medium for Bran and Jon's dream conversation. When Bran thinks,
If I were truly a direwolf, I would understand the song, he thought wistfully. In his wolf dreams, he could race up the sides of mountains, jagged icy mountains taller than any tower, and stand at the summit beneath the full moon with all the world below him, the way it used to be.
, I think it's a memory handed down through time. And the weirwoods are timeless. That's another connection between tree and wolf and the third eye.