I somewhat agree on the other two, but for the first one, Luvdisc and Mamanbou are based off of two completely different fish.
MOVING ON, I don't see how Denchura can evolve from either Spinarak or Ariados. Other than being spiders, I see no similarity between the two. Plus, it's kind of strange for a Pokémon based on a spider to have four legs. Spinarak and Ariados had six. I know, "But Pokefan, Graveler has the four legs and the Golem has two!!!". That makes no sense, but Spinarak and Ariados are supposed to have eight legs, since they're based off of spiders. Instead, they have six. Denchura has a simple four. While I agree that it IS possible, it is highly unlikely that Spinarak/Ariados will evolve into Denchura.