any arrow cut to proper legnth and proper spine will suffice...id try to get a decint weight..i wouldnt go super light or super heavy..
as for heads...id go with a cut on contact head..
I'll have to second that.
With a low draw weight like that, the lowest that is legal in IL for deer, you want to maximize your penetration. Keep a decently heavy arrow and BH's that will start cutting as soon as they touch.
I'd have to recommend against mechanicals (expand-on-impact).
Too much energy lost upon opening, and you want her to keep everything she puts into that short, light draw.