Transformations can be basically whatever you want, as long as they fit into the rough stipulations on the transformations page. A long, prehensile tongue would probably be an uncommon at the least (mostly the prehensile part). Commons can level up to uncommon traits if you get a catalyst for an uncommon trait, but you can't just add two commons together to get something that would equal an uncommon.

Extra eyes can be whatever you want!

Your canon specific questions are hard to answer outside of context - what qualifies as her "official appearance"? Is this a visual medium? I assume not, since it sounds like you're talking about a book. If it's a mostly non visual medium you can use whatever PB works for the character.

I suppose a question regarding the canon is: is there a reason you want to include the content you consider to be OOC, in broad stroke form? What is your reasoning for doing that instead of just making your canon point the end of the first story? I just want to understand the situation.