Yes, these are earlier novels. You can buy them without too much thinking, as the authors were closely connected to the "founding" of Aventuria (Ulrich Kiesow was a Co-Founder, and Ina Kramer was an early illustrator and helped writing a lot of background books).
Of them, I have only read the first book.

"The Lioness" and "The Sacrifice" are about Talionmel, a holy figure of the Rondra church. These books are about her life.