A pity you didn't choose any scene with Túrin in it,
Brinn - I bet that role would be perfect for
Mac.
I won't volunteer since I have practically no talent in anything musical, I don't have a mic, and you will probably find more than enough people with more suitable voices than mine, but I, too, think the Silmarillion one is better.
Having heard
Nerwen's voice sample, I think she'd make a perfect Melian.