Does Jesus Christ constitute only one being or several?
He is one being only, God and man together; and this by reason of the unity of Person which subsists in both the human and the divine natures (XVII. I, 2).
May one speak of more than one will in Christ?
Yes; for in Him there is the divine will in so far as He is God; and the human will in so far as He is man (XVIII. 1).
Is there in Him as man a multiplicity of wills?
Yes, understanding the word "will" in a wide sense and in so far as it comprises the sensitive as well as the intellective appetite; or again in so far as the word sometimes signifies different acts of these faculties (XVIII. 2, 3).
Had the human nature in Christ a free will?
Yes. Although it was absolutely impossible for Him to sin, His will being always and in every sense conformed to the divine will (XVIII. 4).
Next - The Catechism of the Summa - Tertia Pars - XI. OF THE UNITY AND MULTIPLICITY IN JESUS CHRIST: AS REGARDS HIS BEING; AS REGARDS HIS WILL; AND AS REGARDS HIS OPERATIONS (B)