I think she can score in a number of ways, but to your point, watching her guard teammates in her FIBA games was generally very painful. They were terrible directing the offense and getting the ball to Jana, at times looking like they didn't have a clue. Many times the only way Jana could get the ball was to come out and shoot threes. or slash to the basket from the outside.
I wanted to see more of her post up game, but between teams doubling her down low and her team's inability to get her the ball, you didn't have much to form an opinion on her low post abilities, but she scored in many other ways.
Yes I think she will make her layups and benefit greatly from some easy 2's from guards that will benefit her greatly, but I think they also will enable her to show her post up game, and with so many good 3 pt shooters, she won't have to worry about being doubled all the time either.