Despite not being in the teaser trailer, Newton has gone on record saying that she and co-star Wood will be receiving equal pay as their male costars in season three, so she also sounds like a sure thing.
Maeve's journey has been just as interesting as Dolores' and the season two finale heavily implied that Felix (Leonardo Nam) and Sylvester (Ptolemy Slocum) are going to rebuild her. But does that mean she's still inside the park? It seems unlikely that her pearl is one of the five Dolores smuggled out of Westworld, especially since how would Felix and Sylvester rebuild Maeve and then get her body out to Dolores? That doesn't make sense. But perhaps Maeve is the way viewers keep up with the action still happening inside the theme park.
Some recently leaked set photos seem to imply that that is indeed the case, but be warned of spoilers if you choose to click on that link.