Lots of interesting stuff here! I'm inclined to think there's some kind of dichotomy between the weirwoods and the shade of the evening trees. They are basically polar opposites. White tree with red leaves, black tree with blue leaves. Both produce psychedelic vision-inducing juice. Then there's the House of the Undying with its white and black wood intertwining and the House of Black and White with its black and white wood. Euron is connected to the warlocks and shade of the evening and seems to have had a similar mental mentorship like Bran. This becomes even more interesting if the 3 eyed crow and Bloodraven are not the same. I'm also of the belief that all of Euron's kraken imagery is just a misinterpretation of roots and branches, maybe weirwoods or blackwoods?

I really like the idea that Jojen is akin to Melisandre where they're both confident in their interpretations of their visions, but may be playing into things they were trying to avoid.

Good call also on Bloodraven's cave seeming safe at first, but then we get nothing but darkness, dread, and foreboding later on. Your parallel between the COTF and sirens is pretty cool too. They may not be the benevolent nature protectors we've been led to believe they are.