New mockup:

Fixed corners, added wall tops on front view, changed some of the shadows, fixed the bottom of the door, changed the UI a bit. I just noticed some tiling errors, but I'm closing it out for tonight so I'll have to edit it the next time I work on it.
Also started on a portrait:

I'm not sure about the style -- it's not really what I had in mind, not to mention that she's sparkling like a vampire in the sun -- but I was having too much fun to abandon it halfway!

Made a blink animation and a talking one, as well, but I haven't animated it yet.
I'll work more on the animation as well! I've been procrastinating a little bit on that and working on some little bits and bobs with the tiles. I think I'm going to overhaul the pillars and fix the tables next. (And I just realized that the handles on the doors are too tall for a character this size to reach them! Hah. That's what I get for making the tiles first.)
Mike:
Oh don't worry! I might be frugal with my frames but I'll battle my procrastination for sure. Haha.
Sharm:
I am hoping to make her a bit 'bouncier'! Yes, the arms will move but I'm procrastinating on them a bit because I'm not sure exactly how I want them to look. I was thinking I might give her a girly run.
Thanks for the advice about GIMP -- I'll take that into consideration. I tried Microsoft GIF Animator but it needs the frames to be in GIF format (which is the whole problem -- the free version of GraphicsGale won't save GIFs.)

Facet:
I was really hoping I could get away with it, actually. It's easier to see things properly with a semi-top-down perspective, but I really like the look of the characters with a side-on view. I really like your edit, though. I might see if I can get my sprites closer to that angle. Heh! With some tweaks, maybe I can nudge the sprites and the tiles both close enough to each other that they look all right together!
Oh man, I had plans to do some work on the UI, but you have given me some great ideas for tiles. Thanks for the ideas and the links!
Again, thanks to everyone for the compliments~