Well, I tested with Toxic Spikes and it worked.
Well that's it then, Espeon is the best anti-lead. It still needs to worry about Metagross's Bullet Punch and stuff but as of right now, you have to kill it before you can do anything (which means things like Roserade and Smeargle will go down if this is popular enough).
Also, you should keep in mind that since this is a Dream World ability, you will most likely not be able to get Egg moves or Eevee only moves. This means no Wish or Baton Pass.
Edit: I think this might be the best set for an anti-lead.
Espeon @ Focus Sash
EVs: 4 HP/252 SpAtk/252 Spe
Nature: Timid
Ability: Magic Mirror
Psychic
Shadow Ball
Hidden Power [Fire]
Quick Attack
Psychic for STAB and Aerodactyl, Shadow Ball for Azelf, HP Fire for Metagross and Forretress, and Quick Attack to pick off slower priority users and faster Pokemon. HP Fighting could be useful for Tyranitar but it will kill you with Payback+Sandstorm anyway.
Leads that it has a problem with include Fake Out Infernape and Weavile and Extremespeed Lucario, since Fake Out and Extremespeed go before Quick Attack, Metagross, and possibly Bulky leads like Mamoswine, Gliscor, and Swampert. As long as you can KO the former with Psychic+Quick Attack and KO the latter two with 2 Psychics you should be fine.