Was “Waffleshy” supposed to be a companion concept to Twilight’s “I’m pancake!”?  
I wonder what breakfast pastries would round out the “Breakfast Six” (or more)?  
Rainbow Dash - Pop-Tart (for the Nian-cat reference)?  
Rarity - …whatever the Queen of England eats at (semi-)formal breakfasts.  
Pinkie Pie - Pudding (because a cupcake wouldn’t be unexpected enough).  
Fluttershy - Waffleshy as seen above, or perhaps something very humble feeling? A muffin with bits of sweet fruit? But that might step on Derpy’s hooves.  
Applejack - Apple Fritter (“Moah Appla Fwitta?”)
 
Derpy - Muffin
 
Princess Celestia - Chocolate cake.
 
Princess Luna - Mochachino (drunk in the evening of course, rather than the morning, since that is when she gets up)?
 
Princess Cadance - Well, on GOOD days, when their schedules permit, a long-john, eaten in a rather specific way so as to work Shiny up for a return to bed, or for later in the day.
 
Donut Joe - Donut
 
Maud - Pumice? (A nice, fluffy rock, but low on substance, because: junk food/baked good.)
 
Lord Sombra - Crryyysssttaaalllsss.
 
Chrysalis - Love Cat (from the comics)
 
Discord - Spaghetti with whipped cream and atomic fireballs (the candy, not the explosion).
 
Flurry Heart - Spoilered just to be safe: Straight from Cadance’s teat rather than bottled or formula.

Hot Belgian waffles! Excuse my language.

The Flying Waffles (with Fluttershy) screensaver