Regarding why the next Transformers movie is pulling from the Beast Wars canon, Lorenzo di Bonaventura stated that it felt like the prior movies had exhausted the Autobot vs. Decepticons conflict, and he and the other creative minds wanted to show different “tribes” of Transformers.
When not in humanoid robot form, Bumblebee will be driving around in his Camaro form.
We’ll also reunite with Mirage and Arcee, who previously appeared in Dark of the Moon and Bumblebee, respectively.
However, don’t think that means there won’t be any characters from past Transformers movies, as it was also announced that Optimus Prime and Bumblebee will both appear in Rise of the Beasts.