I usually play this piece with pami and that's the way I learned it. But recently when I'm trying to get a nice tone out the melody and trying to add apoyando, I've discovered that my fingers actually want to play it pmip or pamp. It seems to vary depending upon which of my two fingers m or a has a smoother fingernail (and thus, a sweeter tone). I'm the first to admit that this forces a weird jump for the thumb, which makes the chord changes trickier to accomplish (both hands changing positions at the same time). But it doesn't appear to adversely affect the sound. A little hesitation at the ends of the measures seems to help support the uneven 3/4 time (or 9/8 depending on whether you take the arpeggios as triplets or as a compound subdivision).
I'm surprised that I never considered your paai etc. idea to combine the apoyando with a sweep. This is something I may have to play around with. If it were combined with my thumb-heavy idea, the piece could be played with just two fingers. That may make it still easier to focus on the tone of the melody notes, while simultaneously making the timing more difficult. :/ If you're getting this fancy with the piece, then it may be interesting to try a triple sweep piii.