Lance: Gyarados level 68, Kingdra level 66, Aerodactyl level 70, Dragonite level 66, Dragonite level 72 (one of his Dragonair evolved, and the other was replaced by Kingdra).
Rival: Heracross level 71, Alakazam level 69, Tyranitar level 72, and depending on who you chose at the start;
If you have Bulbasaur: Gyarados level 71, Exeggutor level 73, Charizard level 75.
If you have Squirtle: Gyarados level 73, Arcanine level 71, Venusaur level 75.
If you have Charmander:Exeggutor level 73, Arcanine level 71, Blastoise level 75.