Q? - No!

''There is enough of discrepancy [in the gospels] to show that there could have been no previous concert among them; and at the same time such substantial agreement as to show that they all were independent narrators of the same great transaction, as the events actually occurred.”
[Exactly what you look for from the different standpoints in any and every court case before magistrates or jury.]

If Greenleaf could make this statement from his extensive, in-depth studies - clearly 'Q' as  'common source' for the three synoptic gospels must become a failed hypothesis.

 Dead and rotted away.

Theologians - let it go. Bury it!