Not against Ness it ain't. Fire pillars are no joke even with Naryu's, and if you get caught in one, you might as well say goodbye to your stock at high damage since 9/10 he'll grab you. Also with the way the bottom of the stage/ledge situation is, I guarantee you'll have to FW up through the bottom at some point, which leaves you completely vulnerable to any number of Ness's basically guaranteed kill moves (bthrow, bat -- hell, he might even be able to get a PKT2 off).
Lava saves his recovery, but it's not quite so beneficial to Zelda, especially with her light weight. The smaller size of the stage also helps Ness more than it helps us.... just a low ceiling would be fine, but all of Brinstar's blastlines are closer, allowing his bthrow, bat, bair, and uair kill at ridiculously low percentages compared to normal. Even dair can kill relatively early if it's on one of the upper platforms.
Especially... bthrow though.... *eye twitch*
I also don't think the platform layout is especially good for us, but, whatever, maybe I'm just biased against Brinstar. I do know that it's a really good stage for Ness, though, and generally you want to avoid taking your opponent's character to their favorite stage unless yours does 10x better on it. That's just common sense.