This object is relatively straight forward. There is occasional modal mixture with the infrequent use of the F minor chord.
The brief trip to Eb at the end of the object is perhaps the most interesting segment. I am a little disappointed that the only chords we get in this key are dominant chords and we never get a firm Eb. I would argue against a key change here, but the key relationships between C and Eb are interesting for us Riemannians (it is a stacked transformation: parallel then relative).
The most interesting harmonic shift is between the last two chords of the object. A V7 in Eb moving to a V in C. This is an amazing voice leading phenomenon that seems to parallel the key relationships between these two. Since we are going from the V in the key of Eb, to the V in the key of C, we have to perform the transformation in reverse (relative then parallel):
So our base triad the first chord it [Bb, D, F]
R[Bb, D, F] = [G, Bb, D]
In a relative transformation, the chord is transformed into its relative key. So in the case of Bb Major, it is transformed into G minor. This is done by having the top note moved up one step. If the chord were a minor chord and being transformed by a relative transformation, the bottom note would move down one step.
P[G, Bb, D] = [G, B, D]
A parallel transformation takes a chord and transforms it to its parallel major/minor by moving the third a semi-tone in the appropriate direction.
Now, the seventh of the chord, A, does what it naturally wants to do, drops to the G. That release of tension combined combined with the smooth voice-leading in the rest of the chord makes this key transition smooth as butter.