For Ursula's skeleton I used a few human reference images:
I'm still not sure whether she's more human than tree or vice versa but I thought I could have a look at her skeleton anyway. I think the spine on the third drawing is the most likely, but I'll elongate it a little more in Photoshop when I flesh it out. I also played around with giving her a ribcage and seeing how big it would be, the same for the pelvis too. I think they'd both be inhumanly small but because of her skinny frame, they'd actually be quite pronounced.
I also thought I'd look at how her hands might be. I want them to be very long and thin so, as well as using the reference skeletons above, I looked at the skeletal hand of an aye-aye, a very peculiar looking animal:
The left is a copy of the aye-aye hand and the right is my interpretation of a more human version. I definitely want her hands to be this long and thin. As I mentioned earlier, they may become more plant orientated later but it's all very useful anyway!
To break it up a bit I thought I'd give a similar treatment to my dragon-man, who is yet to be named. To do this I used a collection of reference images including human, lizard, horse and snake skeletons:
Again, very rough but it's a nice basis to work from later. I'll elongate the neck in Photoshop but I think this is pretty much the shape he'd have. I couldn't quite decide on how many fingers and toes he'd have but I'm sure I'll decide when I start finalising his design.
After this I thought about a link that Phil had previously sent me, to do with the character workflow you should follow. In it they mentioned making a spreadsheet with columns for certain aspects of your character's appearance or personality. As I'm getting to the stage where the characters need a final design, I thought this would be a great place to start and then visit as I work, to keep me from getting too sidetracked.
The document is a little untidy as scribd didn't seem to like it much but it's definitely going to be useful, especially as I can update it as I work! All good stuff. Now, onwards! :D