#George doesn't /hide/ parallels like that if he intends two characters to be related to each other then he clearly states it

[fromtheseventhhell]

Renly had seemed anxious to know if the girl reminded him of anyone, and when Ned had no answer but a shrug, he had seemed disappointed. The maid was Loras Tyrell's sister Margaery, he'd confessed, but there were those who said she looked like Lyanna. "No," Ned had told him, bemused. (Eddard VI, AGOT)

This is literally people in fandom trying to make shallow connections between Lyanna and [X character] and presenting them as equally important as parallels drawn directly in the text. In fact, this coming after Ned tells Arya she reminds him of Lyanna (in looks and behavior) feels like George cementing the importance of their likeness. Other characters might have passing similarities to Lyanna, but Arya's parallels are much more meaningful than that and are being highlighted for a reason.