Congratulations to your daughter on her new job!
And now, for wardrobe building.
First order of business -- a fantastic puffer coat and possibly a puffer jacket, also. That, along with great snow boots, are going to be the biggest ticket purchases, and if she doesn't have them or doesn't like what she has, she needs an upgrade.
When it comes to pants -- speaking as a former teacher, and as someone who also taught in a small eastern Canadian city -- I would say she could easily manage with mostly denim and ponte bottoms. Obviously the denim should be non-distressed and in good shape.
Teachers in these situations (especially for outdoor ed.) tend to be casual dressers. In fact, if she thinks about maintaining her casual wardrobe but simply taking it a step up to SMART casual, she will probably be hitting the right note. Too dressy won't work for the environment (unless I'm crazy). And if she is biking to work and then outdoors a lot of the time, a true business wardrobe wouldn't be practical. Still, it's perfectly possible to look professional in another way simply by taking care that everything is pristine and cohesive.
She will need skinnies to tuck into her boots, so it's great that she likes them. A pair of trousers in wool in a different silhouette would be a great addition -- keeping in mind that in snowy weather she won't really get much use from wide legs. A skirt (worn with tights in winter) could also be an option for dressier situations.
She probably won't need a suit. But a couple of great toppers ( a blazer and a leather jacket, perhaps) would do a lot to add to the "professional" look she needs without making her stand out as overly dressy for the environment.
When I was teaching I had an indoor job and mostly wore jeans or knit skirts with tights. I also had an admin role for a while and I did have a version of a "suit" for parent or other meetings -- it was a wool riding skirt and a vest with a silk blouse plus tights and boots or shoes (depending on weather). I also had a couple of jackets that I wore regularly with the denim or my other trousers to dress those up.
She also needs to let go of the tees in favour of some fabulous knitwear. Luckily, that should be easy to find this year, and since oversized is in, she can go to tunics or longer lengths if she likes.
I would also suggest some scarves to add interest and texture and warmth. And of course some shirts/ blouses.
In terms of footwear, she will probably be able to wear her Blundstones much of the year with jeans, to be honest -- if she gets the chisel toe version, it is pretty versatile. If not, she can try a dressier version of the chelsea boot as a step up (or for indoor days). A tall boot would also be great.
In terms of what to buy -- Angie's business casual capsule for spring is a great place to start. Change the items, change the style, change the colours -- but the numbers here give a great starting point.
For designers or stores that have the aesthetic she wants -- maybe AllSaints (can be ordered online in Canada)? Danier for the leather, of course. She can probably also get a great bag there.