About the whole Ayla-Glenn-Frog-Schala thing... I'm still more for Glenn replacing Ayla, rather than Schala. A very short picture would just look contrived and odd - though she might in truth be short, the sprite in the original didn't appear so, so to shrink it makes it look like a cut corner. About Ayla's running sprite being smaller... well, can one not then make Glenn in a similar fashion, hunched over at least. He was a frog for so very long, there's probably some of that left in him. I don't know... as neat as Schala would be, I've still heavily on the Glenn side. Personally, I think the best solution, if both are no implementable, is to poll all those involved in the project, and see what the general concensus is.
Oh, and about the email... is that all there is? Just those few changes? Or were you going to send the entire story?
Regarding the changes, though... two things. Firstly, Kasmir is, I think, a very good name change from Serran. But secondly... I'd be wary about calling the bioweapon Geddon. The reason is, remember the Tower of Gheddon in Cross? Yeah, it might have an h in there, but it's the same name. For that reason I'd be a little wary. Maybe some other Revalations reference? Apollyon, which is 'Destroyer', maybe? Or, if you want the whole last-battle reference, it would be better not to splice the name at such an point, taking Armageddon and taking geddon from it, as though that was the second part to the name. It's Ar-mageddon, after all, or Har-Megiddo. In that case, if you want something similar to Geddon, I'd sugest Megiddo.