Re-
It is not quite the same thing, this musical passage is more a variation on a theme where the first note is the melodic line (that we accentuate in general to make it stand out)
we can play the theme then first variation in eighth notes and then 2nd variation in triplets of eighth notes (as in return of the swallows) then for the extra strong in 3rd variation with 4 sixteenth notes
If you know the java CA GAZE, you have a nice example of this kind of variations in the three rhythms (eighth note, triplet-eighth note, sixteenth note) in the TRIO in D major.
To come back to the tremolos, while waiting to be able to play them regularly (and in the tempo!!!) it is better to replace them by "plated" chords of 2 or 3 notes respecting the keys and if your accordion has a full musette register, use it by playing the passage to the higher octave: guaranteed effect!!!