Then what in the world do you classify as hadeeth? Hadeeth is the sayings, actions and approvals of the Messenger. The hadeeth that we know today are the recorded forms of his actions, sayings and approvals. Believing in the Messenger :saws1: and all what he came with is a part of belief, how can one say the shahaadah (i.e. There is none to be worshipped except Allah and Muhammed :saws1: is His messenger) and claim to believe in the Messenger but doesn't believe in anything that he said or did? How can you make a separation between the person and his actions? Did Allah send a person carrying His message to someone who isn't fit to be followed?
It's like I tell you that your father was the best businessman that ever lived and you need to follow his example if you want a successful career. Your father dies one day so you write everything in a book to preserve his success, for yourself and for future generations to be as successful. Is there any difference between seeing your father's success in real life and writing a book about it?
Then what is the difference between obeying the Messenger's example and everything he came with while he was alive and calling the recorded forms of his life hadeeth after he passes away? Allah is far removed from sending a man whose character, conduct and actions we cannot take from. The Qur'an was revealed to him :saws1: so there must be something about him that Allah saw that no one else in the creation possessed: the best and the most noblest of character. He was the best of all the prophets and Messengers, he is the best of creation and the most beloved to Allah from all of His creation. Allah sent the best message, the Qur'an, to the best of creation because only the best of creation possesses all those qualities that the rest of creation must take as an example and obey in all matters if they hope to possess any good. To disbelieve in this is disbelief in the Qur'an so your argument is flawed and is the opposite to what the sahaba and righteous scholars have understood hadeeth to be.
From the understanding of the sahaba, these verses are precisely telling us to follow hadeeth and from this one can see that rejecting hadeeth is disbelief in Islam.