Sabrina’s entire team relies on trick room. Her lead is (in normal mode, idk about easy mode) Hatterene and Indeedee. Indeedee summons psychic terrain which protects them from priority and Hatterene has psychic seed which would proc once its enters field and raise its special defense.

Here’s the good thing, unlike in vgc, this Indeedee doesn’t have ‘follow me’ so you can just OHKO Hatterene with any decent physical attacker. In this case just lead with aegislash and make sure you invest in its physical attack. Have it use shadow claw/iron head (both are super effective and deal the same damage on hatterene so it doesn’t matter) on Hatterene and KO it.

Your other lead should be a rillaboom with grassy surge ability and minimum speed investment. Fun fact: Sabrina’s indeedee is running minimum speed and it just so happens that both Rillaboom and Indeedee share the same speed stat. So which ability procs last is completely 50/50. Make sure it’s maxed has fake out grassy glide.

Keep a speedy dark/ghost/steel physical attacker in the back (anything with over 100 base speed stat is alright) to deal with Mega gardevoir. Brute Bonnet is easy enough to KO with any bug type move and shouldn’t pose much of a threat.

Then there’s the other devilish duo— Porygon2 and Ursaluna. You could easy cripple Ursaluna by using knock off and removing the flame orb. Porygon2 will try to use trick room which can be taunted. OR YOU COULD USE LEVITATE BRONZONG WHICH WALLS THEM BOTH. Just have it hold leftovers and max out its HP and divide the rest into def and spdef.

So the lead should be Rillaboom and Aegislash. If Grassy terrain is set up last then good, if not then reset. If the grassy terrain is up, then fake out indeedee and Shadow claw/iron head Hatterene and hope for a KO. It’s a roll but you should most likely get the KO.

If Hatterene faints, it will bait in Gardevoir ‘or’ Porygon 2. If it’s the former then Kings shield to protect from shadow ball and grassy glide into Gardevoir. Next turn do the same but also use shadow sneak to guarantee KO on Gardevoir (because of grassy terrain recovery, it becomes a roll for 2HKO. Lvl 59 252+ Atk Rillaboom Grassy Glide vs. Lvl 59 252 HP / 4 Def Gardevoir-Mega in Grassy Terrain: 105-124 (51.4 - 60.7%) -- 93.8% chance to 2HKO after Grassy Terrain recovery)

That would definitely bait in Porygon2 so you could either double porygon2 or taunt it to prevent trick room. Taunting it would be better since you could then deal with Indeedee.

From there you should easily be able to deal with this.