Hey! That sounds like a lovely proposal. I've worked in the classroom with similar material to help children learn English through small animations of songs, and the visual content is of great aid to them.
I do work with 3D animation, and since my specialty is character creation and modeling, I think we'll be able to work out a good design. I do like to present possibilities to my clients for them to choose the best option, so the time can be extended depending on the feedback received. But within 7 days I believe we can establish the design and get a model with proper topology, ready to be rigged and then animated. While the actual animation process will definitely take longer and the time of completion depend a lot on what needs to be animated, I'm willing to complete up to thirty seconds of content for this price.