It seems like Jolla is going for a combination of #1 and #3. They're aiming to be compatible with existing Android hardware, they've made it easy to preview the

It seems like Jolla is going for a combination of #1 and #3. They're aiming to be compatible with existing Android hardware, they've made it easy to preview their OS on existing devices without making the switch outright, and they're targeting select countries first so that they can use their momentum to move into other countries (rather than overextending their reach from day one).