Byron's pokemon are:
Bronzor - lv 36
Steelix - lv 36
Bastiodon - lv 39
Only two of your pokemon are close to that. You chould try and level up your lower pokemon so they are all around level 35+.
Although, Empoleon can probably take out most of the pokemon because of the ground and rock weakness. Definitely level up Ponyta to get a fire advantage. It also evolves to Rapidash at level 40 so will be way stronger then.