Unhappy Freshman

“At the end of the Winter quarter, I’d like to tell her to come home (which would mean she’d leave without finishing the final Spring Quarter of freshman year. Is this a bad idea?”
YES! Its a terrible idea.
She needs to finish her winter qtr at the very least.
Then, if she absolutely refuses to go back, then she should ask for a leave of absence, but that WILL negatively impact her transfer chances. Colleges will want to see a complete transcript, not a transcript full of W’s.

“Will this look bad for transfer applications?”
YES!
Colleges expect transfer applicants to be able to show that they can handle college level work.
And transfer applications are not even looked at UNTIL after MAY, after the college knows how many new Freshman will be attending the following year.
She should finish out the year in order to give herself the best chances to be able to transfer
. My bet is that she will feel differently in a few months.