I dont think these sort of questions are allowed on here
but I'm going to answer it anyways.
Elesa's Pokemon are:
level 28 Emolga.
Trait=Static
-Quick Attack
-Pursuit
-Volt Switch
Level 28 Flaaffy.
Trait= Static
-Thunder Wave
-Volt Switch
-Take Down
Level 30 Zebstrika.
Trait=Lightningrod
-Quick Attack
-Pursuit
-Volt Switch
-Flame Charge
1-Lucario) your Lucario only needs 1-2 more levels to be able to beat Elesa, it would take normal damage from everything (accept for Flame Charge) but wont be affected by Static becuase it's probably (and preferably) a special attacker. However it will take SE damage from Zebstrika's Flame Charge
2-Dewott) dont bother too much with Dewott (obviously Electric>Water)
3-Magnemite) I would recommend getting Magnemite to level 25-27 (it resists 2/3 of the Pokemon Elesa has) and will be useful againt Emolga and Flaaffy (not against Zebstrika Because it will take SE damage from Zebstrika's Flame Charge)
4-Herdier) Herdier would probably be the hardest to train due to it's low level, but it's the only useable Pokemon you have (other than Dewott which you shouldnt use) that wont take SE damage from Zebstrika's Flame Charge
how to train?
either backtrack and battle every trainer you've missed or use wild Pokemon. remember, this is an ingame battle so overleveling is the best way to go.