Get 3 Eevees 3 Different Ways:

This isn't a cheat but you can do it.

1.Get the national dex and then go to BeBes house and she,ll give you eevee.

2.Beat the elite four and go to pal park and migrate eevee from a game boy advance verson of pokemon.

3.Use the pokeradar until you find eevee.

Hope this helps.:)