I'd say 2 is the lie, Yvonne? The other two just seem more probable.

Yes, the lie is 3. Ashla was hardly educated as a child.

1.) Felicity is quite smart, but hardly has an education to match. Her research as an alchemist has pushed her a lot farther in terms of maths and sciences. Things like language arts, social studies, art, etc. are still very basic.
2.) Felicity has considered chopping her dead pinky off. However, she's afriad of cutting it the wrong way, bleeding, and/ or getting hurt in the process.
3.) Felicity was initially left handed, but her early childhood experience with her pinky being twisted and killed forced her to switch to using her right.