Unknowns
I think it's hilarious that people call out 'unknowns' like actors just appear on the streets. I don't know anyone who has a big movie as their first acting credit... everyone has experience somewhere. Nothing wrong with casting actors that you've heard of...
Shooting schedules and ages
They'd have to shoot the little kid adventures for the entire trilogy all at once, basically, in the same year, then reuse them whenever link travels back in time, assuming we borrow from that aspect of OoT.
On silent Link
I think making him a man of few words could go a long, LONG way towards making the elf badass. I wouldn't mind it at all, as long as, y'know, he still did some acting.
My casting so far
Grown Link: William Moseley (Narnia) with one major acting credit, this guy is unknown enough for me, has the look down pat, and has already started on his sword training.
Princess Zelda: Emmy Rossum (Day after tomorrow) Just a beautiful girl with a calm sweet demanor
Ganondorf: David Wenham (300) the voice, clearly, and not as overexposed as Gerard Butler
Little Link: (completely stumped... they don't have a lot of these young guys y'know?)
Little Zelda: Elle Fanning