This is ultra-determinism that has no support in the Book of Genesis as written. Esau is shown wanting the soup, hesitating, weighing the benefits of it against the primogeniture, and deciding for the soup. Rebecca is shown building up a complex intrigue in order to co-opt Jacob and fool Isaac. Isaac nearly succeeds in discovering the truth. If the inspired author wanted to convey automatic preordainment, he failed utterly in this literary task; but if he wanted to depict a conflict of independent wills striving to their respective goals and priorities, he succeeded brilliantly.
God doesn't speak in riddles.
There was no intrigue or conspiracy on the part of Rebecca and Jacob. Jacob bought the birthright in a fair bargain. Every one got just they wanted based on their experience and educated decisions. When Jacob bought the birthright he was entitled to the blessing. He in effect, became the "eldest". If anything it was Esau and Isaac who were trying to cheat Jacob out of his blessing and God provided a way for Rececca to overhear the conspiracy and thwart it. It saved Isaac from disobeying God's plan for Israel. All of these events were orchestrated by God.