God doesn’t need anything at all. Not men, not Our Lady, not to take flesh and dwell among us. Yet, he has willed many things. It is especially shallow the idea that God would create creatures in order for them to rebel. You confuse the freedom of will granted to all creatures (even the spiritual ones) with the Divine Will (which is holy and does not will sin or evil).
The book “
Fundamentals of Catholic Dogma” by Dr. Ludwig Ott brings together some essential teachings of the Church and is a standard reference. There we find:
Any dogma is an infallible doctrine, divinely and formally revealed by God as a necessary truth for salvation. Infallibility on matters of faith and morals pertains to both the Extraordinary Magisterium (an ex cathedra pronouncement of the Roman Pontiff or a de fide statement of an Ecumenical Council) and to the Ordinary Magisterium (the perennial teaching of the Pope and the Bishops in union with him around the world).
In this context, we have different theological distinctions. When we say
De Fide, we mean a teachinng of the highest level of theological/doctrinal truth. When we say *Sententia Certa *we mean a theologically certain opinion, without final approval but clearly deduced from revelation. When we say
Sententia communis, we mean a common teaching widely held, and generally accepted by theologians, but not dogmatically asserted. (
source)
In short, the above is the official teaching on the angels (very summarized, of course) which is known to be truthful.