Finally, constructive criticism!
But, yes, to address the underdeveloped characters, I was limited to ten pages maximum for this story in particular (what I have takes about nine). Had I been given more, even fifteen maximum, I definitely would've given the characters some more definition and make them feel less under-cooked.
As for gesturing, I tried keeping all "generic" gestures to Ellie (for good reason -- it's hard to describe sign language accurately, especially if you don't have the time to look up everything the character is saying). Any actions by other characters, I tried describing fully, but I suppose more show and less tell wouldn't hurt.
But, thanks for pointing it out, Jerkface Heh. If I get to revising this story, which I probably will, I'll keep that in mind.