If a developer states something that he created has always been intended, it's objective that it's the case. Even if it was badly conveyed (which it hasn't been).
No, whether or not Link is a proxy is a subjective matter than can only be substantiated on an individual basis. Doesn't matter whether the developers intended for Link to be one thing or another; the player is prone to interpret him as something completely different. Link is nothing set-in-stone. He's whatever the player makes him, respectively.