I'm not sure. On the one hand, official articles and trailers say how Barbie: It Takes Two is explicitly a 26 episode series. It also has a slightly more story driven approach compared to the episodic nature of Barbie Dreamhouse Adventures. On the other hand, it's possible that there could be more. This article from years ago says how Barbie: Dreamtopia is 52 episodes while Barbie: Dreamhouse Adventures is 26 episodes when it's actually the other way around.
Even if there are more episodes, there isn't a guarantee that everyone could come back. Case in point, for Dreamhouse Adventures, Ann Austen (the showrunner) was credited as creative producer for the first 26 episodes while Julia Pistor would be a co-executive producer and Grant Moran would be story editor. They both left, and she took over as co-executive producer and head writer for the last 26 episodes. Some of the people who worked on Barbie: It Takes Two have already moved onto other projects, like staff writer Crescent Imani Novell moving over to DreamWorks Animation Television, and story editor Kendall Michele Haney moving onto to be story editor for the Nick Jr show HexVet.
https://www.awn.com/news/mattel-announces-two-new-animated-barbie-series-tv-special