Your sketches are great, from what I see you will be very good as a car designer overall and fit the Tesla brand.
I agree that you can adapt your sketches more towards a coherent philosophy, and stick more to brand guidelines.
Take them as a challenge more than a rule. I like how you explored options for the grille though since leaving it out while retaining a suggestion of a grille as Tesla is doing with the Model 3 is not a very strong solution.
You explore a lot and in that some sketches don't make too much sense for the project, but that is something you develop with time. Some sketches are right on the spot so overall your design work is very strong. Keep the illustrative touch, it makes the sketches stand out. I also agree loose sketching helps a lot in the early stages, working on developing volumes together with lines and then translating your findings to the car, rather than immediately thinking from a 'this has to be a car' viewpoint.
You are being given a great chance, many people go into transportation design to then step into automotive but never find a chance to get into the industry. Don't push too hard, you are a great designer.