Originally voiced by Richard Mulligan, Einstein is an old, large, dim-witted Great Dane who lives in Manhattan. He is incredibly kind and loyal despite his lack of intelligence. Einstein will be part of 2 of the movie's musical numbers (however, as these are still being written we don't know how many lines he will have in these) so you must be comfortable with singing for the role. 

We are looking an imitation that is as close to the original performance as possible. Here's a clip for reference (Einstein comes in at 1:30) https://youtu.be/vwTy_iCmGmA