Matching with Zelda's current canon point sounds good then! She'll still be Sheik to him, though at some point she may reveal herself to him as per canon point due to the event!

I'm fine with filling in the game canon with some manga canon for personality/mannerisms. I played Link here a long time ago and he was pretty much game canon, though I took a few things from the manga just to expand his personality a bit. Zelda is purely game canon, not much other than icons is taken from the manga for her, but I don't mind you doing so for Link since he has far bigger gaps to fill in than Zelda does game canon wise!