I'm not so sure about whatever reason Sheryl wants him. I guess he saved her during the concert in the newer version, but that doesn't really compare to all the things he (heh, I wrote "she" first) did for Ranka/Lanca.
In addition to the awesome flying and combat in the beginning, we got a good amount of background on the main characters this time:
Alto is actually descended from a line of Kabuki actors, received training for years, and is probably the geisha in the OP. I had thought that was Sheryl in heavy makeup until they revealed that. That explains his feminine appearance very well.
Lanca is a 1/4 Zentradi. Perhaps that explains why her hair gets a little floaty sometimes and she can even control it a bit?
The real mystery is why the aliens are after her. Particularly when she sings, they wake up, or start hunting her down and chase after her. I'm not entirely sure whether they are after both Lanca and Sheryl, since the parts at the end had them together. For now, I'm leaning towards them only going after Lanca, and not Sheryl. Maybe that could be a hit to Sheryl's ego?