NMoasis: my preference is to have them blooming early spring, so they need to be planted now.
SallyG: I thought about placing the styrofoam box over the container-planted bulbs, but the ground is frozen & it would be more difficult to check the containers to ensure they don't freeze. We will be getting snow through February, so that's an additional hindrance regarding access.
RpR: great idea, but the ground is frozen & I'm inclined at this point to place all the containers in the garage (not insulated) & bring them out on days when temperatures climb above freezing.
Thank you all for your contributions - it's quite a challenge when your zone differs radically from where your previous residence was located. As usual, there are pros & cons!