Jack could be a better option for Eczacibasi, though I am not sure what is their plan since they have 3 sliders (Yasemin, Beyza, Gibbe) and Ergul (who hits from zone 3). Would be smarter to transfer an another MB who hits from zone 3 like Veljkovic.
As far as I know, GS was interested in Gibbemeyer. Now the rotation is probably towards Belien since they can't afford to transfer Jack, unless she accepts a lower salary for the sake of being close to her fiance, who is also an MB, Murathan Kisal (ex GS player too).
As much as I like Gibbemeyer as a player, it'd be a better option signing Beliën, simply she's contributing more on court and probably cheaper than the American.