I find your analysis a little convoluted. The opening four measures are a sequence that can be found in baroque figured Bass and, as you said, quite commonplace.
The is F # minor. So the opening four measures are V7 (with the tonic interestingly serving as an anticipation), i, V7/III, III
As you mention what is interesting is how Chopin handles it. Especially knowing Chopin's two favorite composers and the ones he went to for models were Mozart and Bach. In this phrase you hear/see the influence. Chopin takes the F# E# and D C# heard in the opening melody as a motivic unit and employs it as a countermelody in the alto to the sequential repetition of the melody a third higher. Note too how in the chords in measure 2 and 4 exploit the potential E# and E cross relation (though here it isn't a true one), Finally the chromatic sequence of harmony which proceeds after this phrase is a development of the F#, E# (or E), D, C# motive by chromatic motion. Finally the descending 4 note motive implied by the first statement of the phrase (F#E# D,C# later F# E, D C#) can be viewed as an inversion of the melody's upward motion. So within these four measures, Chopin creates mirror voice leading while later employing the descending line and the potential cross relations to expand the harmonic palette of the piece.
Oh and one final note - the third beat C# in the low bass msr 1 to F# first beat msr 2 low bass - the inversion of the downward 5th motion is "reflected" in the upward motion of C# to F# in the first beat of measure two. This "mirror" game is repeated later in the phrase.
So what bearing does this have on the execution? Well, you need to know what a mazurka is to be sure you stress the 3rd beat. Chopin helps you out with the suspension and voice leading, the only caution is not to accent too much the low bass notes in the left hand first beat. Also, understanding how the right hand is put together gives a clue to the touch and articulation requires - the clarity required for a baroque fugue and the melodic line bel canto (which is derived from early baroque opera). The difference? The folk influence is much stronger and the textures are more idiomatic to the piano (though the lineage comes from Mozart sonatas) than ever before as well as the harmony being far more chromatic.