How do Arbiter and Johnson get to earth before chief to pick him up at the start of 3? Johnson and Arbiter were on the ring when Chief went to earth.
I don’t think they do get there before him. Some time passes between when the Keyship arrives at Earth and when Chief falls into the jungle to be found by Johnson. Johnson gets back to Earth on Nov 15, 2552. Chief doesn’t get there until 2 days later. This is because the Keyship didn’t jump straight to Earth, but rather jumped closer to Jupiter and slowly made its way to Earth over the course of 5 days. These events are described in Halo: Uprising.