HEADCANON
The reason that Maeve still allows Celine to keep the lab running is to run Maeve's own personal tests to convert her back to human from a beast. As we know, Maeve is quite proficient in concealment and transformation magic (Arthur), and Elven technology has created the gears to accompany magic, such as automatic cauldrons.
Hence it is fair to say that Maeve is working on her own project for the such.
Also, the trial dungeons are actually houses of gnomes that once inhabited the forests