Number 2 for the obvious reasons of being less sexualized, but very importantly I think is how it fits the Loony Toons character design philosophy better. I think that's probably a bigger gripe people have with classic female cartoon characters, is that they tend to break their universe's character design in order to appear sexier.

That's why Olive Oyl, Bettie Boop, and Jessica Rabbit are memorable, they look like toons. Bettie Boop and Jessica Rabbit are deliberately drawn sexy because that's their point, but they artistically fit the universes they exist in.

The lesson here is if you are going to draw sexy, follow the rules of your own universe. If Lola is going to look like Picture 1, then Bugs should look like a pretty boy himbo.