As the NewAdvent article points out, you cannot really escape the ‘fact’ of Angels in the scriptures. While I personally think that Paul’s ‘identification’ of certain choirs is a pretty far stretch, it is rooted very firmly (and unquestionably) within the Church Tradition (although not exactly firm Dogma).
Pseudo_Dyonisius (Dennis in some places) gave us the most structured hierarchy, as listed by B&B, but this itself was claimed by D to be based upon the Tradition he received from his teachers which filled in the blanks enough to go from the overt but disconnected scriptural references, to the ‘polished’ schema he articulated. However, nothing I have studied on these works suggests that they were the result of anything other than (possibly inspired) intellectual speculation, rather than any sort of ‘angelic revelation’ where an Angel came down and said, “this is what our world is like”.
So, aside from their existence, which is De Fide, the rest is interesting speculation handed down to us for centuries (ok, over a millenia…), that while representative of the Church’s tradition on the subject, is not itself actually ‘binding’ to the Faith.
