How did the Messenger of Allah, Allah's peace and blessings be upon him, hear the animals, and did Gabriel inform him that the owner of the camel was starving it?

There is no contradiction between the Prophet Muhammad's understanding of the camel's complaint and Prophet Solomon's prayer to be granted a dominion that no one after him should have. This is because the Prophet's understanding of the camel's complaint does not negate Solomon's exclusive and complete dominion. Furthermore, the Prophet's hearing of the camel's complaint is established, and he understood it directly without the mediation of Gabriel.