Winter Coats for Analysts?

Jcrew on the cheap or brunoc on the premium.

Get a nice wool overcoat + scarf

if you are willing to search, some amazing, high quality overcoats can be found at high end vintage stores

Nice, thick navy wool overcoat. If you're lucky you can score decent discounts for some of the better known brands (now might be a good time to look). You can try vintage/second hand, but ymmv. Otherwise, I'm pretty sure there is a decent D2C brand out there that offers good overcoats.

moncler for casual. knot standard or black lapel for work. both are above your budget but these will last a long time if you take care of it

Patagonia or Northface should be in your price range. If you're in Canada, try MEC.

is it okay to wear a moncler coming to work? do people wear only suit jacket or suit+jacket?

Check out Woolrich - sometimes they have good down jacket models that would fit nicely over your suit and are a blend of formal / casual that you are looking for. I had trouble with the Goose recently as they tend to leak lots of small feathers for many months following purchase.

Patagonia is a good option too.

Get the Michigan goose