Ash decides to pull the raft by first stripping down to his boxers and then swim in the arctic. Even though this is anime, swimming in the northern waters would cause anyone either to drown (which almost happens to Ash) or catch hypothermia.
Lapras having telepathy is absurd, as it's completely unclear why. And that the PokéDex states that Lapras can "understand human speech" isn't unique since all Pokémon can.
Wouldn't Jynx being on the raft add like an extra 90 lbs. to the load? Which would make the Water Pokémon, and later Ash move at a slow pace. Also, Psyduck not swimming only added more weight.
Misty the Water type gym leader uses Ash's Pokédex to look up Lapras, is preposterous.
Brock and/or Misty should have performed CPR on Ash due to nearly drowning.
It's unclear where Ash, Brock, and Misty got their raft and rope from.
Santa using Ponyta as reindeer is straight up illogical, as Ponyta can't learn fly. However, the Pokémon Stantler didn't exist yet.