Semitonal Appoggiaturas In Mozart's Variation II

In Variation I, Mozart embellishes the theme with mostly semitonal appoggiaturas. The harmony in the bass line remains the same as in theme, it changes only rhythmically. The character abruptly changes in bar 5 with a switch to forte. The right hand echoes the rising thirds from the original, but with appoggiaturas on the fourth quaver of bars 5 and 6. A trill is added in bar 7. The same technique used in bars 1-4 is used again until bar 17, where the texture goes back to that found in bars 5-8.
In Variation II, the melody line is once again reminiscent of the theme, as are the semiquavers in the bass line which are played as triplets. The right hand is decorating the original theme with trills and descending perfect fourths in scalic demi-semiquavers.

Clearly, these variations offer more contrast. But do they also "round off" the form? Characterise their role in the structure, both in terms of their musical material and their affect (expression). In what ways is the coda an effective closing gesture for this movement?
In Variation V the theme gets obfuscated once again, the slow tempo being the only noticeable connection between the theme and the variation. The character of this variation is quite tranquil and reflective as the tempo itself implies (Adagio), but the demisemiquavers and the staccatos in scalic passages definitely bring in a certain kind of agitation which is amplified by the sudden dynamic changes (f-p). The descending scale at the end of bar 3 had been used previously in Variation II. Bars 5 and 6 contain an octave leap in the accompaniment which is reminiscent of the octaves in the bass line in Variation

Bars 1 and 2 of the melody line use appoggiaturas with added acciaccaturas in a similar manner to Variation V. Similarly to Variations I, II and V, there is a sudden change in dynamics and texture in bar 5. The right hand 's semiquavers are punctuated by arpeggiated chords in the bass line. In bars 7-10, the bass line changes back to quavers. Also, bars 9 and 10 are reminiscent of the passages in Variation III. Bars 13-16 are reiterations of bars 1-2 with acciaccaturas added to the offbeat quavers in bars 15-16. Bar 17 introduces another sudden change from piano to forte and semiquaver arpeggiations in both hands. In the second time bar, the rising A major scale, also found in bar 9, propels the coda. The coda swiftly introduces new material: from beat three of bar 20 there is a decorated descending scalic motion from E to B in the melody line which is afterwards restated in semiquavers, finally reaching the tonic A. The piece ends with powerful perfect