(Before getting started, I'm sorry that I drew the explainations here so bad because I drew them all as phone, since my computer got jammed with this so please understand this \*sob)

  
So while I was rechecking Wartwood Frog kiddo's official human forms from 'The Shut-In!', I found out Sprig has bridge-and-round nose(like Anne's), Polly and Maddie have round nose(like Marcy's), and Toadie has upper hemioval nose. After the truth that we can headcanon everything about Ivy's human form like cloths or hair and other features, I couldn't imagine how would her nose shape be like, because I didn't think Ivy's nose would be same with other girls.   


But then, I just fount out there might be a pattern here... that their nose shape follows their frog form's head shape! Sprig has protuding upper lips, Polly and Maddie's head shape is round as tadpole, and Toadie, has no chin (and angled head). And finally, Ivy has chubby cheeks.

So I imagined myself, would it be side-lined or upper-lined? And I gathered these two candidates are my best: smooth-lined-nose-bridge-and-round shape, or pyramid shape.

  
I personally prefer the second one, because she's short and chubby unlike other girls, and it actually matches well when I adjust it to her. So yeah Here it is :3

  
Sorry that I rushed with the drawing, I had no time to rest actually (for my personal schedules). I hope you enjoyed my theory, at least a little!

While I was think about how would Ivy's human form be like, suddenly I made up an 'Frog's Human Form's Nose Theory'. Here's my Ivy's human form take, and the folowing images are the explaination of my theory: