You never know. According to Bianca, the triplets were the only Gym Leaders that she couldn't contact at the end. Maybe that's because they're actually the Shadow Triad.
'shudders'
He said the triplets not being Gym Leaders anymore would be a hint for them being the Shadow Triad, and I said that it doesn't make sense because we already had the Triad in BW, when the triplets were Gym Leaders. If they are the Triad now, they were the Triad in BW already. So no, it's not a hint or an evidence of anything.
In the original games the manual had a type chart that said Ghost was super-effective against Psychic.
Any eight-year-old who charged into the Saffron City gym with a Haunter or Gengar discovered that 1) Ghost attacks did no damage to Psychics, despite what the manual said; however, 2) the only Ghost attack which used the standard damage formula was Lick, rendering point 1 moot; but 3) all the ghosts in Gen I were part-Poison, so they were weak to Psychic-type attacks.
Actually, if I recall correctly, the developer's intention WAS for Ghost to be SE on Psychic, but they fucked up something (lol RBY) and it did no damage instead.
Also, wanna see something really cute?
That's from a FRLG guide, if I recall correctly. They hadn't even held that new move contest yet and, coincidentally, the move chosen (DRACO METEOR) was almost the same as this Meteor Rain move.