While looking through Disney animation reels on Vimeo, I found some Good Dinosaur animation tests from 2013, which I'm guessing is the only piece of animation we have of the original version so far.
Nice find! It's pretty clear the model appears to be Arlo, but I just am a bit confused because the description says the character at :26 is based on Kaa from the Jungle book and the video describes the file as "pupsmod_JakeSnake_animation". Is the idea that he used the artist used the dinosaur model at the studio for a personal project and just described it as being Kaa from the jungle book instead of Arlo?