Which Avatar: Fire and Ash editor is named first in the infobox?

The Avatar: Fire and Ash editor named first in the film's infobox is Stephen E. Rivkin.

Rivkin is an American film editor whose credits include major studio productions and earlier entries in the Avatar series. He previously co-edited Avatar and Avatar: The Way of Water, making him a continuing member of James Cameron's editorial team for the franchise.

Fire and Ash was not edited by one person alone. Its post-production involved a collaborative group of editors, reflecting the unusual demands of a large performance-capture and visual-effects production. Cameron also participated in the editing process, while editors including Nicolas de Toth, John Refoua, Jason Gaudio, and David Brenner are associated with the film's editorial work.

The question asks specifically who is named first in the infobox, not who edited the movie exclusively or who was the sole lead editor. Those are different questions. Rivkin's placement at the beginning of the listed credit makes his name the canonical answer, even though several other editors contributed substantially.