??? Pantheism is the view that everything is of an all-encompassing immanent God; or that the universe, or nature, and God are equivalent. There is nothing even remotely suggesting this. The Reformers simply said that God is sovereign giving His grace to whomever He so wills.
Faith, then, as well in its beginning as in its completion, is God's gift; and let no one have any doubt whatever, unless he desires to resist the plainest sacred writings, that this gift is given to some, while to some it is not given. But why it is not given to all ought not to disturb the believer, who believes that from one all have gone into a condemnation, which undoubtedly is most righteous; so that even if none were delivered therefrom, there would be no just cause for finding fault with God. Whence it is plain that it is a great grace for many to be delivered, and to acknowledge in those that are not delivered what would be due to themselves; so that he that glorieth may glory not in his own merits, which he sees to be equaled in those that are condemned, but in the Lord. But why He delivers one rather than another,—"His judgments are unsearchable, and His ways past finding out." [Rom. 11.33.] For it is better in this case for us to hear or to say, "O man, who art thou that repliest against God?" [Rom. 9.20.] than to dare to speak as if we could know what He has chosen to be kept secret. Since, moreover, He could not will anything unrighteous.
Augustine, A Treatis on the Predestination of the Saints
I say that one is BEGINNING to stray into Pantheism, because your view does not give creation the ability to bring about secondary causes. Thus, creation is an extension of God which has no inherent ability to act apart from it.
The Reformers simply said that God is sovereign giving His grace to whomever He so wills.
Does God giving man the ability to procreate (cooperate in creation) intrude on His sovereignty? If not, why then do you claim that when man cooperates in the spiritual realm, it infringes on God's sovereignty? If a woman says she can give life through the means that God has given her in the natural sense, what is to keep us from saying that a Christian gives "birth" to good deeds based on the graces that God has given us? That it is "our" work? In both cases, we cooperate in God's creative work.
Regards