If your reason for starting this thread is to concentrate on the traditional Trinity doctrine, I will save you the time and effort. You cannot disprove the Trinity with the Qur'an, but you can with the Bible:
Trinity Debate
Unitarian Universalist churches are growing in numbers, however these churches are not Christian and many members are atheists who deny the existence of a creator god. Biblical and evangelical unitarian churches are not "growing rapidly".
As to the Infancy Gospel of Thomas, what scholars call a manuscript is not the issue. This issue is the accuracy of what is written in manuscripts that are apocryphal and myth. The only difference between the the clay bird account is that in the Thomas manuscript the 5 year-old Jesus broke the commandment concerning making images, which he then brought to life and Allah giving life to clay birds made by a disobedient child. What the Qur'an has to say about Mary is found in the Protoevangelium of James, which is also apocryphal and myth.