I don't live there, but I spend a lot of time there in the winter because my daughter is in a winter sport that frequently takes her there to compete; we just got back last night, and will be heading back up in 2 weeks. Since I'm always attending these large events, I'm often walking around cities in snow and freezing weather from distant parking locations, so I have a bit of appreciation for the cold-weather pedestrian experience.
By "does not drive" do you mean she doesn't own a vehicle/never got around to learning, or does she have a medical reason for not being able to drive? (Rhetorical question; I'm not looking for you to actually tell me.) Because if it isn't the last one, the first thing she should do to prepare is learn and get a license, and preferably get her own vehicle. If she will be on a large campus there is likely to at least be a car-sharing service so that she can borrow a car for grocery runs, etc. (If she does have a medical reason, she should budget for lots of paid rides.)
The biggest issue with walking everywhere when it is cold and snowy is safety. Dealing with the cold is one aspect, and you've gotten a lot of advice about that (I'd add that silk longjohns are my very fave for comfort for all but the very coldest days), but it is also important to understand that snow in the Lake Effect belt isn't usually *removed*, rather it is moved. Into *very* large piles (some places do vacuum up excess snow and dump it in remote locations, but that's pretty rare except in affluent communities). When I say very large, I'm talking sometimes 20 feet tall. By law, the really big piles are supposed to be created well away from roads, but that doesn't always happen if it has been snowing for days on end. Sidewalks may or may not be cleared in commercial areas, but if snow is being plowed off the roads it often ends up constantly spilling over onto sidewalks and berms, so that each time you cross an intersection you may have to step through at least a foot of it, and may get drenched with chemical slush from passing cars on a major road. This means she needs not only boots, but knee-high boots, and a water-shedding coat and pants. (Most people who work indoors without having to go in and out all the time will bring regular shoes to change into so as not to wear the heavy boots all day. A pair of loose ripstop pants can be worn the same way, as a moisture-resistant 3rd top layer over regular pants and long underwear) Drivers whose cars are not properly cleared off may also have poor visibility even for days after storms because the road chemicals create a white haze on glass, so she should make it a point to wear colors other than white or gray outside in the daytime, and to wear/carry something reflective (like an armband) if walking at night, so that drivers can clearly see her.
https://www.michigan.gov/-/media/Project/Websites/msp/ohsp/pdfs5/2020_ohsp_winterdriving_passengersandpedestrians_infographic_72.pdf?rev=f3982ca4bb7f4040bec358850c0fcde5#:~:text=Safety tips for pedestrians include,before stepping into the street.
Ice cleats for her boots are a good idea just in case, and she should also be aware that if she customarily uses a backpack, that will affect her balance walking on ice, and needs to be compensated for. Oh, and if she needs to wash puffer coats, she'll need tennis balls for the dryer to keep them from getting lumpy.
PS: One last thing: ordinary nylon or polyester fashion tights/leggings are NOT sufficient on their own to protect from sub-freezing weather. If you are outside for any appreciable period of time in the cold (except for hard exercise like cold-weather running) you need to have at least 2 layers on your legs, and the fabric of at least one layer should be insulating. This is the goof that gets most Southerners when they travel north; they will bundle up in a (short) coat, gloves and a hat, but neglect that space between the top of the boots and the bottom of the coat. If she is a dress-wearer, a full-length down coat that reaches a little past the knees is doubly important. (FWIW, Eddie Bauer has good full-length down coats, and are doing major markdowns for Black Friday. Columbia and Land's End are also good outwear sources that won't break the bank.) As other folks have said, think layers. She should primarily invest in a couple of good lightweight down coats with hoods, quality insulated boots, a good scarf or two, at least 2 prs of good thinsulate gloves (b/c gloves are easily lost), a balaclava, lined windproof pants, and bottom base layers. The tops she already has can probably be layered enough under her coat, so no need to invest in sweaters or specialty base-layer tops right away. BTW, someone upthread mentioned wool socks. Those are great -- unless, like me, you have issues tolerating wool next to your skin. If that's the case, silk or synthetic technical sockliners are also important.