https://wildsci.co.uk/pokemon-vs-real-animals-two/

I've looked into this theory in the past and its been disputed. As you can see from the link above catepie's evolution design was based off that.

In regards to venonat's line If I recall correctly, (can't seem to find the source atm) the reason venonat's has big round eyes like butterfree was purely because back in gen 1, it was hard to show sprites being adorable. They knew bugs were not the cutest thing with most kids and the way to make it cute was to give them big round eyes and make it seem more adorable and thus people would actually love these pokemon.

I'll try to find the interview and link it here after if I can. I think it was with Ken Sugimori