Firefall

6) Invasions/Recovering held watchtowers. These essentially spawn off of Drop Pod events if they are left around too long. The Chosen will take over, or attempt to take over, a watchtower. You must stop them and take it back.

Not quite right. Close though. And theoretically closer in the future. Any Chosen wandering around can potentially take a watchtower, whether spawned by Drop Pod, Incursion(Warbringer), or somebody thumping too close to the Melding. Invasions are something different, and are currently disabled. There's also calling in fresh SIN towers, which is similar to retaking watchtowers.

The eventual progression is supposed to be Drop pod -> Chosen secure area and towers -> Fortify into an Incursion -> Launch Invasion on nearby city(Copa/Tans-hub/Sunken).
Only Copa Invasions have been enabled previously, and even that was on a timer (3 days shard uptime) rather than Chosen status. Last few patches have added Invasion defenses to Trans-hub and Sunken Harbor, so we may be seeing them turned on again soonish.

Note: Retaking towers and Incursions are by design intended for groups. Invasions flat out require several of them if you want to win.

Another note: Now is actually a very good time to be getting started, as the Chosen have several known bugs in their AI, making them far easier to deal with than normal.



Looking at the list again, the events you didn't specifically mention are the Pirate hijacks in the Sunken Harbor arena, and the sensor mission in Cerrado plains, though I haven't gotten that one to repeat. And the race goes in both directions, though the starting line in Copa is tricky to spot at first.