Yup, Andre is more Manectric than Houndoom. XD Hell, it even has fabulous hair! XD Heatran is a Special Attacker with 106/106 defenses. Zygarde is a closer match...100 Attack, 121 Defense. XD Tyranitar is low on Speed, but...I think it's probably the best match out of the 600s...I mean, Latios is an awful fit...probably better for Mira or Andre. XD Genesect is also a good option for Dante's 600...because I see Dante as having very close Atk and Sp. Atk, while the difference between Evie's is more drastic. XD 

What base 600 has such a drastic difference (above 35 points) between Atk and Sp.Atk aside from Tyranitar anyway? I think poor Speed below 90 can be overlooked in this case.... XD

Andre: Jolteon/???/Mega Manectric
Selena: Milotic/Diancie or Meloetta/Mega Venusaur
Dante: Blaziken/Salamence or Genesect/Mega Charizard X
Jayden: Carracosta/Zygarde/Mega Scizor
Evie: Weavile/???/???
Mira: ???/???/???
Cisrian: ???/???/???