Do the shoulder cook as planned. Leave the ribs out on your counter for 2-3 hours to get the thawing process started, then put them in the fridge overnight.
When you get up early to do the ribs, pull the shoulder and put it in the oven at whatever temp you were cooking at. You're not really taking on more smoke at that point, just using your charcoal as a heat source. Do whatever you're going to do to fit all those ribs, toss some more charcoal and smoke wood in the WSM, and get to whatever temp you use for ribs. Cook the ribs, and if you timed it all right then everything will be done.
If I were you, I'd target 10am for a finish time, meaning you're probably tossing those ribs on around 5am. That gives you a couple hours of wiggle room. Everything can be left on the counter for 30 minutes to cool a bit, then wrapped tight in foil and put in a cooler with a bunch of towels to stay a safe temperature for hours.