ALL GOOD BOYES

Yeah but Lillipup is based on Terriers. A Retriever is probably closer to the Growlthile line.

Yeah, but growlithe doesn't have 3 evolutions

The charizard evolution tree was used because aside from pikachu (the individual Pokemon) it is the best known Pokemon (including evolutions) so the meme would relate better to everyone and not just hardcore fans, since a lot of people are only familiar with the 'famous' Pokemon

Also because who doesn't want a charizard?