From what I could find of Eleanor in Starkey’s, Virtuous Prince, there was a discussion of a proposal between Phillip of Burgundy and Henry VII about two possible betrothals. Henry would marry Eleanor, and Mary, his sister, would marry Philip’s infant son, Charles. No firm betrothal though.

Here is Isabella’s response to Henry VII upon his request to marry Katherine himself; Isabella reacted with horror. “a very evil thing–one never before seen, the mere mention of which offends the ears.” That was the end of that discussion. Henry then opened negotiations with Ferdinand for Henry and Katherine.

Eleanor was a baby in comparison. Henry had known Katherine for years. She was available and of childbearing years. I can’t see Henry waiting for Eleanor to grow up. Henry did have affection for Katherine at this time and he held her in great esteem. For him, I think the choice was obvious.