Breakfasts are the toughest meals to share. If you're just looking for something light it's possible. I was traveling with my two kids and we used our saved credits (from meal-sharing) to buy CS breakfasts. We were able to split 2 meals between the 3 of us and we felt ok, but certainly not full.
We ordered Mickey waffles with bacon. They were VERY generous with the bacon (one plate had 9 slices and the other plate had 10), but the waffles are smaller than your typical Belgian waffle.
In the past you were able to also order a "dessert" with each meal, which could be a donut, pastry, muffin, bagel, etc. That option was removed from the plan, but apparently SOME of the resort food courts still let you do it. If you can find one that does, then meal-sharing for breakfast becomes a lot easier.
The other thing to keep in mind breakfast at the resorts is that you can get the largest size bottled beverage with your meal on the
DDP (OJ, powerade, nesquik, etc). If you use your refillable mug with breakfast, then the DDP drink can be taken with you into the parks or stored in the hotel room for later.