Hello, hope this helps,
For the ghost e4,
Samurott and chandelure. Samurott is a tank that can learn mega horn leveling up (bug type move with 120 power)
Chandelure is the highest sp Atk fighter in the game and can basically crush all of shauntels team with shadow ball.
You can train Musharna, but their painfully slow. Chandelure can learn psychic (special attack monster). Scrafty and Archeops can learn plenty of dark type moves, level them up by another 5 or so levels and you should have no problem.
You can basically crush him with your scrafty once you level it up some more. I would reccomend spamming brick break, ore teching it focus blast through tm and hiving it an accuracy raising item to hold (like scope lens which also raises critical hit ratio).
Mega horn. Her sigilyph is annoying so teach one of your Pokemon thunderbolt and one hit ko the thing.
The champion alder half of his team are big types, so have Archeops learn Ariel ace or another reliable flying type move (but don’t forget to do some leveling up, if you have your team at at least 50, the e4 are a breeze but alders Pokemon are in the 70’s :( so I would do some serious leveling up unless you go with the type advantage and 1 hit ko his whole team.
His vanillite is weak to fighting type moves so scrafty can beat it easily, scrafty can also take care of his bouffalant (a normal type). His druddigon is annoying, but Archeops learns dragon claw at lv 56 or by Tm.
Hope this helped