MAJOR SPOILER WARNING FOR THE UNAWARE
Throughout the entire show we see the characters an anthropomorphic animals. This is because of how Odokawa perceives them. It is also a major plot point that this perception allows Odokawa to easily identify people and distinguish them from another. In the second half of the final episode, we then get them as regular people, who look similar to their animal counterparts, but also definitely distinct from it. There are also some other ways the show uses to distinguish these different headspaces, e.g. the line work being rather sharp in the second half of the final episode when it was always fuzzy throughout the rest of the show.
Unless you spend a ton of money on CGI animal people (in which case, why have live action at all), or you strike out one of the major plot arcs that has impact on a number of other story points, this show simply cannot be live action. It uses the medium of animation as a mechanical device to facilitate its plot.