If your friend's Lileep's details was legitimate, in being that it had an ability it could have, moves it could actually learn, stats not above what they should be etc. it may possibly be able to get through Pokémon Transporter.
I myself have transferred many Pokedit Pokémon to Pokémon X and Y, all of them legitimate some have got through some haven't.
Obvious hacked Pokémon such as Spiritomb with Wonder Guard will be prevented from being transferred over, as will Pokémon that can't be legitimately obtained such as a Shiny Lugia with Multiscale.
Hope I helped :)