potential for everything analyzed to be incorrect: very high. with that said, here are my results.
26. Iaug, ii, Iaug, ii6, viidim, I
27. bVII, I6, I, i65
I think that of the mixture chords included in these few measures the one that most surprised my ears was the bVI mixture chord in measure 28. Up until then Mozart uses mostly one and two chords (tonic and predominant chords) so you think that measures 26 and 27 are going towards a five or dominant chord. But instead Mozart is a butt-head and goes into a bVI chord. yep, that's it.