Q. Can i also claim head of household for the 18 year old?
A. Simple answer: yes.
As you appear to know, the key element is where does she "live". Being away at college is only a temporary absence and she considered as living with the parent while away at school. Not being considered a minor is irrelevant. If you're confident that her living situation amounts to her changing her domicile from mom's house to yours, then you can claim HoH. It's a borderline situation. Usually the student is still considered domiciled at the home she left from, for school, unless she does something concrete to change it (e.g. mailing address). Where doe she keep most of her stuff. Does she have or own bedroom.
