Im thinking in having Minerva's handmaiden to be some spellvaster to help aid in that front, as Minerva will be pretty much melee and support oriented.

That said, I was thinking i three options, but I guess I'll have her be a Transmuter / Mage of the Arcane Order, which would give the spellcasting and some versatility (through spell pool resourcefulness).

Her banned schools would be Evocation and Necromancy, and she'll get the Spontaneous Divination ACF for some info gathering and scrying purposes.

She has made an oath to protect Minerva since she was a little baby and look to her as her own granddaughter, so when Minerva decided to steal her brother's place to this mission, she came along and aided her with her magic to help them arrive safely.