There is no clear plan to add a grappler soon but the needed mechanics are comming so it will be a possibility. Projectiles will come first with next planned characters 😉
In the online menu, the "Settings" section has an "Update" entry. It is deactivated on emulator but will dowload the latest version and reprogram your cart with it on physical version.
In case something would go wrong, you will have the option to reset to the factory version.