You can always try level grinding if you don't care about time.
Breloom's special attack is really bad, and Juan has 2 ice attacks. Don't make Breloom use grass attacks. My best advice is going to the move reminder to teach Gardevoir calm mind and psychic, and then teaching it some other special move that can hit Crawdaunt (preferably thunderbolt). When Juan uses Luvdisc, you can just max your special stats and sweep.
Why are you using 2 fighting Pokemon? I recommend putting one of them in the PC so your other 5 Pokemon can get more experience. You should probably also put Aggron in the PC because it has bad physical moves, special attack, and speed.