Rhoda's comment, and Ellen being shorter / smaller / heavier / blonder and held by Rhoda in the last panel, weren't originally planned. Rhoda was primarily chosen because I wanted her in there somewhere to show that Susan had become the same height as her.
As I was deciding on a pose for Rhoda, however, it suddenly occurred to me that Rhoda could literally do everything that was being listed, and to greater extremes (as was explored starting in Part 2 of Escape From The Mall).
Rhoda's claim to fame will always be being the best at resizing people (both entirely and partially), but she can also do a lot of other things, too. Rhoda is basically as close as a person can get to being a really powerful wizard without technically being a wizard (by EGS's definition, which requires the ability to learn other people's spells), so she can branch out a bit. Nanase is similar in her diversity of spells.
I do like, however, characters having themes to their magic, and Ellen's theme is transformation beams. She might deviate from it at times, but for the most part, that's her thing. Considering Ellen's spells from that perspective has proven fun, and we'll be getting into the (possibly predictable) ways they can be extra fun next week.