For those of us that feel they HAVE to get a Din's into the match somehow, try shielding the first grenade to backward Din's so you're falling back as the Din's goes toward Snake. It probably won't do anything, but at least you're attempting to cover yourself better than saying 'hey, I feel like getting blown up as I try to burn you.' ^_^;
Seriously, this matchup is HORRIBLE because of the disjointedness on... everything Snake has. You're going to have to bait ANYTHING Snake has in order to feel remotely safe with doing anything offensive. And even then, it's possible for him to recover faster from the cooldown than Zelda can approach due to her lack of speed. True, once you get Snake into the air, the matchup looks a lot better, but the hard part is getting Snake into the air in the first place.
As such, I'd say go to your most comfortable stage, since I can't think of any level aside from ones that hurt you that make Snake go into the air. The Metroid levels would be ones to look into... but Norfair can screw you over instead of helping with the random lava/fire waves, Frigate's flip is really the only thing that could possibly help you(and the right side of the level hurts both of you a ton), and Brinstar is a tiny level. Snake can tilt you all he wants there and have almost no backlash from it. So unless you're EXTREMELY comfortable on those stages, I wouldn't recommend it.
You might want to seriously think about water stages, like Delfino and Japes(if it isn't banned). If Snake falls into the water, then you could spam Din's or go for a gutsy dair, and dsmash can help set these up a bit better. And if you're both in there somehow on Delfino, I'd look into weak bairing to push him into the water and away from you, or fastfalling a nair into the water over and over to keep dragging Snake in to either do a lot of damage or setup for an opportunistic dair, since nair is faster than just about anything Snake can do(unless his back is to you...).
EDIT: Not sure EXACTLY if DI on the nair could turn the tables on you, so if someone can look into that that would be amazing. It'd still be something you might be able to pull off once or twice before having to do something else.
Japes opens the window for the stage to help you get a ton of free damage because of the current, and if he has to land, it's commonly right where you're standing, which makes it a lot easier to knock him back out there. He'd have to risk you hitting him back out, dtilt locking if he's in the right %s, grabbing the ledge, or getting around you to the stage behind you. Zelda has an easier time of these because of the vanishing properties of Farore's, but don't overestimate it, and dear lord do NOT land next to Snake unless you can't help it! Just beware of Snake instead knocking YOU into the water in either stage, as he can torture you, too, on recovery. These are mentions where if you notice you can make him feel pressured, they might be viable if you're EXTREMELY careful. Otherwise, I agree with the neutral picks as stated before, since you don't have to worry about random shenanigans messing you up/helping him out.
In any case, I would say Snake is only slightly easier than Meta because you have more options against him then Meta, especially in recovery and overall anything in the air against Snake. Though it's hilarious to kick/spike Meta out of his up B if he gets too greedy and you somehow can predict it(I've done it to people before, so don't think I'm just speaking theoretically). ^_^
