A Brief Background on Ulrich Zwingli, Swiss Reformer

Zwingli was, in some respects, an anomaly. On the one hand, he was a reformer faithful to the Scriptures. He insisted on the sole authority of Scripture before Luther raised his voice in Scripture's defense. He taught emphatically salvation in Christ alone and in His perfect sacrifice. He emphasized strongly the truth of sovereign and eternal predestination and preached it from the pulpit. He correctly and vigorously opposed all the Romish practices contrary to Scripture. He was instrumental in laying the foundation for the beginnings of covenant theology. 

But, on the other hand, he never quite shook free from his humanism. He held to the end his notion that heathen men of renown could be saved. He taught that all children in the world who die in infancy go to heaven. And he continued to his last breath to admire Erasmus, that humanistic enemy of the Reformation.

[Click here to read the entire article:  Zwingli]

Unfortunately Zwingli's theology that all children who die in infancy go to heaven is an error that has been repeated by modern Anabaptists like Roger Nicole and many Evangelicals.  Yes, even particular Baptists are basically Anabaptist in their theology of the sacraments and salvation of children.  The Reformed view is that baptism is a sign of the covenant of grace and that the children of elect believers are promised salvation.  (Acts 2:38-40).

But this article should suffice to show that Zwingli's basic theology was not in agreement with the Remonstrandts or the Catabaptists/Anabaptists since Zwingli upheld infant baptism and unconditional election as the basis for that baptism.