After his surprising firing, James Gunn has received the support of hundreds of thousands of fans and of the main Guardians of the Galaxy cast. Even if most consider that his jokes were indeed offensive, the tweets themselves didn't explain the abrupt firing.
In this way, it was reminded that James Gunn did apologise for those tweets a while ago. Furthermore, Disney also knew (at the time of the hiring) who Gunn was. So his dismissal made no sense whatsoever for most of people.
After the cast of the Guardians of the Galaxy signed a support letter, the rumours started to appear saying that Disney will rehire the director. Various outlets based these rumours on the document signed by the cast, as well as on the fact that Disney isn't apparently searching for a new writer and director.
Aiming for a 2020 release date, Guardians of the Galaxy 3 should begin shooting early next year. But at the moment Marvel has no script and hasn't announced a screenwriter. James Gunn did submit a first draft, but we can safely assume that Disney wants to cut all ties with him.
According to Variety, in an exclusive report, Disney has recognized the force behind this movement to support the director. However, even if some of the actors would choose to quit, they would face legal action, since they are under contract.
Furthermore, Walt Disney Studios chairman Alan Horn already said that Gunn's tweets are indefensible and inconsistent with the studio's values. So it would make no sense to contradict these supposed values by rehiring James Gunn.
At the same time, Variety also reports that Disney and Marvel Studios are in no hurry to find a replacement. Guardians of the Galaxy 3 is supposed to enter production in February 2019. However, we guess a delay won't surprise anybody at this point.