Todd Spangler NY Digital EditorDisney Plus will be the only place to watch “Mulan” — but you’ll be able to pay $29.99 to purchase access to the live-action remake through third-party device platforms.Available starting Sept. 4, “Mulan” will be available to Disney Plus subscribers who pay an additional $29.99 early-access fee, on top of regular $6.99-per-month subscription.