The only real "counter" I've found for Sneasel is Shellos. Simply because it's not 2HKO'd by anything that Sneasel has and can recover off the damage, but it's still weary of a crit.
Your OP is kind of wacky, though. Aerial Ace is pretty much never used because it's coverage is kind of redundant with Ice Punch and Sneasel doesn't really want to hit Fightings. Most Yanma and Sneasel carry Life Orb as well, since the power increase in Life Orb is really important sometimes. For instance, with Sneasek vs Yanma:
236 Atk Life Orb Sneasel Ice Shard vs. 0 HP / 0 Def Yanma: 18-26 (78.26 - 113.04%) -- 93.75% chance to OHKO
236 Atk Eviolite Sneasel Ice Shard vs. 0 HP / 0 Def Yanma: 14-20 (60.86 - 86.95%) -- guaranteed 2HKO
Eviolite Yanma is a decent check, though. Ice Shard is a 2HKO, however you're slower on the first turn, which means that you're forced to run Protect or you'll be OHKO'd by Ice Punch. There's also Stealth Rock.
236 Atk Life Orb Sneasel Ice Shard vs. 0 HP / 0 Def Eviolite Yanma: 16-18 (69.56 - 78.26%) -- guaranteed 2HKO
Your OP is kind of wacky, though. Aerial Ace is pretty much never used because it's coverage is kind of redundant with Ice Punch and Sneasel doesn't really want to hit Fightings. Most Yanma and Sneasel carry Life Orb as well, since the power increase in Life Orb is really important sometimes. For instance, with Sneasek vs Yanma:
236 Atk Life Orb Sneasel Ice Shard vs. 0 HP / 0 Def Yanma: 18-26 (78.26 - 113.04%) -- 93.75% chance to OHKO
236 Atk Eviolite Sneasel Ice Shard vs. 0 HP / 0 Def Yanma: 14-20 (60.86 - 86.95%) -- guaranteed 2HKO
Eviolite Yanma is a decent check, though. Ice Shard is a 2HKO, however you're slower on the first turn, which means that you're forced to run Protect or you'll be OHKO'd by Ice Punch. There's also Stealth Rock.
236 Atk Life Orb Sneasel Ice Shard vs. 0 HP / 0 Def Eviolite Yanma: 16-18 (69.56 - 78.26%) -- guaranteed 2HKO