Is Ariel related to Hercules

Under Greek mythology King Triton (who is Ariel's father) is Poseidon's son. Poseidon is Zeus' brother. Zeus is Hercules' father. So King Triton is Hercules' cousin which makes Ariel and Hercules first cousin's once removed.

Well I'm not sure where you heard that, and there fictional characters but no they are not

You, sir, are a moron.

Zeus and Poseidon are brothers. Ariel is the daughter of Poseidon and Hercules is the son if Zeus. So yes, they are cousins.

You were close, see the above improvement.