I'd go with druid. It gives you a reason for high wisdom and the aspect of merging with animal minds. High Charisma for persuasion and intimidation, probably a background supporting intimidation.

The fact is that she can do super impressive magic, she just usually chooses not to, so you'd definitely want to go with a full caster.

Yeah, I agree with druid as the base. She did a shapeshifting duel with one of the archchancellors, as well as her borrowing, and that's the class that uses it the best.

But don't forget that she was a hedge doctor and midwife as well. She'll want healing proficiency. She'd have some kind of bonus for perception with humans imo, even if it was DM fiat rather than a class skill.

But she's definitely multi class since she pulls off a huge time manipulation ritual, can planar travel (at least if you count her going into the realm of death to retrieve Tiffany Aching as planar travel), and similar feats that would normally be non druid types of spells.

There's also This little adaptation that might help

you're thinking about it wrong. She tries as hard as she can to never use magic. her one spell she uses is a fancy Magic soul jar spell and maybe detect magic. For what she does you probably want a psionic.