The steep roof should keep all the heavy snow off your greenhouse.
You can choose to put vents in the roof and the sides of the greenhouse to circulate the air and manage the temperature/climate inside.
A good thing to note is the metal sides of the shipping container. IN my design, I’ll experiment with covering this with siding or not. The metal sides are great conductors of heat, and could very well heat your greenhouse and home in winter. However in the summer it will get very hot. Michael Reynolds said his original Earthship design got so hot it endangered the building so he had to modify it so it wouldn’t be so efficient at heating.
At this point it would be easier to add the log/wood siding BEFORE connecting the greenhouse. Or if you prefer not to put on siding that’s up to you. In northern climates which get very cold and southern states which get rather warm, insulating your shipping container becomes an issue. There are many ways to insulate. You can insulate the interior but if you stud the interior walls and sheetrock over that, that will make you lose up to 53.33 square feet of space inside per level. It might be better to get some spray foam insulation and put it on the OUTSIDE of the building and then cover that with wood siding of your choice.
NOTE: Cut the holes for the windows BEFORE adding the siding.