What types of foreshadowing are in this novel?

Thea's uniqueness and greatness are foreshadowed at the beginning of the book when Dr. Archie finds her sick at her parents' house as her mother is giving birth to a younger brother. Dr. Archie says to Mr. Kronberg, "You've got a very sick child in there. Why didn't you call me before? It's pneumonia, and she must have been sick for several days." By recognizing that Thea is sick and by giving her care, Dr. Archie likely saves Thea's life.
Dr. Archie also recognizes Thea's special quality, which is lost on her family; he thinks to himself, "And to feel no responsibility about the little girl. Silly old goat! The baby would have got into the world somehow; they always do. But a nice little girl like that—she's worth the whole litter." Dr. Archie's rescue of Thea foreshadows her future greatness and also foreshadows the way he will rescue her in the future by giving her money to study in Germany. Dr. Archie's gift saves Thea from being financially reliant on Fred Ottenburg. Though she cares for Ottenburg, he is married, and it is better for Thea to rely on Dr. Archie for financial support. In this sense, he saves her metaphorically after literally having saved her as a child.
In addition, Thea's sickness as a child foreshadows her later sickness that brings her to Arizona with Fred Ottenburg. While she is studying in Chicago, she becomes sick from the cold, gloomy weather, and Fred proposes a trip to see the cliff-dwellings in Arizona. This sickness puts her at Fred's mercy to some degree, and she only realizes later that he is already married. Therefore, her earlier childhood sickness is a precursor of this later sickness, and her childhood sickness and her rescue by Dr. Archie are also signs of her future greatness as a singer who will move beyond her simple roots in Colorado to sing in Germany and New York.