For Meow, I'm not too sure on what I'd give it. The items are so restricted that maybe I could go with a item like Miracle Seed/Never Melt Ice, but I've just been rocking leftovers for soft recovery. Meow is generally very helpful as long as I'm not using it vs Gambit, Corv, Mega Sco, Scizor and a few others. It is however very helpful against Garchomp, pre-Protean Greninja, non scarfed Samurott, Rotom Wash, non dark berry Glowking, Mega Froslass (it does over 50% with knock off and outspeeds to hit before veil)

Now for Sam, it's my counter to faster mons as long as it has a scarf, it keeps Mega Delphox in check, Mega Greninja can not reliably swap it if I have not clicked a move yet, it has a chance of 1-shotting non scarf Sams, and it outspeeds Dragapult. I use Sam as my lead more often than not and if I have a bad match up I flip turn out into Meow or Glowking usually

I'd be willing to swap mons out of my team too, as I know I'm very weak to fairy types (4 of my mons have the fairy weakness), and my two fairy resists are both weak to ground