I don't think we can appeal to any consensus regarding some version of a Two
Source Hypothesis. Who has done the count, and what constitutes a scholar?
Do you mean the "Farrer Hypothesis"? (and not Ferrier?)
I prefer to think of it as the MwQ Hypothesis (Mark without Q). My own
research is suggesting to me so far that my conclusion will be closer to MwQ
than Mark with a Q. I am especially influenced by the work of both Mark
Goodacre and Maurice Casey ("An Aramaic Approach to Q")
As for the different birth narratives being stumbling blocks, see Mark
Goodacre "The Case Against Q" pp. 54ff.
Matthew's birth and resurrection narratives may have, according to the MwQH,
initially inspired Luke to rewrite Mark with his somewhat different accounts
of Jesus' birth and resurrection. Matthew provides Jesus with messianic
pedigree, tracing it back to Abraham, as the son of David, but Luke carries
the lineage further back to Adam as the son of God. Luke introduces themes
progressively developed throughout his gospel. Jerusalem and the Temple and
the connection between the births of Jesus and John are major elements in
his birth narrative.
Napier, New Zealand