While you make some valid points, Drokas is kinda right. Bulbapedia is no more fan speculation than your theory is... There is no fact stating that Poliwrath and Poliwhirl are or aren't frogs or tadpoles. I think that they could be just as much on either side because, as you point out, there is evidence proving both. Some dex entries are figurative, but at the same time, some aren't. Theres honestly no telling what they really are without knowing from GameFreak themselves.
While its true that the Polis have the bulging eyes, no tail, and limbs, they also still have the swirly belly whether it be theme or not, round shape, and small legs. I also don't entirely believe that they have wide mouths, they're kind of just one of those Pokemon that have a mouth that isnt represented. They have no wider of a mouth than Diglett, Voltorb, or Surskit. Also, the fact that Politoad, a member of their evolution line, is classified as the Frog Pokemon while the others are Tadpole Pokemon, says something to me. We also need to consider that Satoshi Tajiri created Pokemon based on his love of catching bugs and tadpoles as a kid, for all we know he could have asked Ken Sugimori to create him a tadpole based line to signify that.
All in all, they have traits of both to me. I know that a tadpole is classified by having a tail and no limbs, but this is Pokemon and Pokemon doesnt always make sense. For now I'm just gonna call them Teenage Mutant Ninja Tadfrogs.
While its true that the Polis have the bulging eyes, no tail, and limbs, they also still have the swirly belly whether it be theme or not, round shape, and small legs. I also don't entirely believe that they have wide mouths, they're kind of just one of those Pokemon that have a mouth that isnt represented. They have no wider of a mouth than Diglett, Voltorb, or Surskit. Also, the fact that Politoad, a member of their evolution line, is classified as the Frog Pokemon while the others are Tadpole Pokemon, says something to me. We also need to consider that Satoshi Tajiri created Pokemon based on his love of catching bugs and tadpoles as a kid, for all we know he could have asked Ken Sugimori to create him a tadpole based line to signify that.
All in all, they have traits of both to me. I know that a tadpole is classified by having a tail and no limbs, but this is Pokemon and Pokemon doesnt always make sense. For now I'm just gonna call them Teenage Mutant Ninja Tadfrogs.