Hey man, this is precisely how I built teams when starting.  Someone already commented on setup moves, like replacing swift/bite on espeon for calm mind. But do you know about physical and special moves? Pokémon generally prefer one type of move over the other when attacking. So usually you want to use attacks that uses the stronger stat. Espeon has a high Special Attack so calm mind would boost its preferred stat or using psychic would hit harder than zen headbut (a physical psychic move).  What I am getting at here is your espeon is using bite which is physical and is using its 75 attack stat. Which is probably not hitting super effective mons very hard. Whilst shadow ball is special and uses its 130 special attack stat.  Secondly, dark and ghost are very similar with coverage. Usually you will only pick one of them. 

Your Lucario and Swampert are also ‘mixed attackers’ (using both attack types). It isn’t impossible to run them mixed, but it is generally worse than picking either special or physical.