Interesting times we live in...It's possible Apple will still go with Hyundai / KIA. Seems there is A LOT of speculation being generated from this news, especially now in Japan. Although Mazda might make a great partner, it seems like Nissan or Mitsubishi would perhaps be a better match because they are large scale manufactures with EV experience.
I think Mazda has a lot of pride (as they should) and is laser focused on its own brand and product development...Partnering with Toyota makes sense....Partnering with Apple...Not so sure.
That said, in my view, Mazda has the best design sense and could use this partnership as a way to boost its overall business and become a more influential auto manufacturer.