How would Thomas Hobbes, John Locke, and Jean-Jacques Rousseau react to the American Revolution?

Jean-Jacques Rousseau would have loved it - but he would say it did not go far enough. Rousseau would not want private property to be protected. He thought it was the cause of conflict in society - promoting man's proclivity to be greedy. Actually, Rousseau may have written about it since he was alive until early July 1778.

You could look up Rousseau's writings to check this.

Montesquieu would have applauded the use of his idea for the separation of powers in the new American constitution if he had lived to see it.

Thomas Hobbes would have hated the thought of abolishing the monarchy. He would have questioned the idea of people voting en masse and governing themselves. Hobbes did not have much faith in the intelligence of most humans.

John Locke would have approved the idea of revolution and the content of the Declaration of Independence - since many of his ideas were borrowed by the author Thomas Jefferson - but I don't think Locke would have trusted a democracy where all people could vote. Actually, he may have approved of the final U. S. Constitution in 1787 because it allowed the vote only to white men with property who were presumably more intelligent. Most enlightenment thinkers had little respect for the wisdom of uneducated people. So Locke would feel better knowing that poor people, Africans, and women could not vote in the new United States of America.

[ I disagree with Locke - I think women are equal to men in all ways - but that was not the thinking in the 1700's among the intellectuals - who were all men.]

You can look up the writings of each of these philosophers to draw your own conclusions. It's always difficult to know what another person might think.

You might also look up Voltaire. I feel sure he would have been amused by the whole thing.