I think you need to listen to Young Hunting again, or at least have a look at the text. There's very little overlap between YH and TOK - certainly not enough to suggest hybridisation. Near the beginning of YH (not the tail end) a lady tries to get a talking bird onside by promising it a cage made of glittering gold, but (a) it's a fairly transparent ruse to kill the bird & (b) the bird doesn't fall for it. The only thing it has in common with the bargain at the end of TOK is the reference to a gold (and ivory) cage.

Nic Jones sang a version of TOK with a first-verse repeat on his second album ("And he's followed her up and he's followed her down", etc). I hadn't listened to that much folk when I first heard it, and it took me ages to work out what was going on ("he came back?"). I don't think the first-verse repeat works with ballads generally.