You'll later appreciate the fact that the broken mons exist. I used to hate it but later on I realized it's just Ame's attempt at making her own meta that isn't Smogon. I didn't appreciate it till much later but, better late than never right? (Also, if all of the broken pokemon existed in Reborn's Meta we would see a lot of Shaymin-S, Deoxys-A, Deoxys-N, and Darkrai everywhere. >>)
Back on topic. The above suggestion works better as Chansey can wash away a lot of the use that Blissey used to have with it's eviolite. But a suggestion for a trapper would be fairly obvious. Gothitelle, while a trapper is massively overshadow by two other trappers in the meta that have served an amazing purpose. You have either Dugtrio or Chandelure.
Chandelure (M) @ Choice Scarf
Trait: Shadow Tag
EVs: 252 SAtk / 4 SDef / 252 Spd
Modest Nature ( +SAtk, -Atk) / Timid Nature (+Spd, -Atk)
-Overheat
-Energy Ball
-Shadow Ball
-Hidden Power [ice] / Trick
You'll fair a little bit better with Chandelure. Chandelure has the ability to halt many standard sweepers in this game and is the bain to any pokemon with a Choice Scarf/band/specs. In the Reborn meta, we all know. NOBODY likes to face this thing with a sweeper that's frail to a specific attack Chandelure has. With this specific set you will be able to threaten Landorus, Landorus-T, Breloom, Gengar, and various other pokemon. The nature is really up to preference. I like Modest because it has a great chance to OHKO Mamoswine. Timid is usually the preferred nature because in the Reborn's meta speed is a major factor as a lot of sweepers are extremely fast like Excadrill or Ludicolo.
Good luck with the perish team. It's a very cute and interesting concept. Hope the suggestions help!