Jazz Kitchen Express is a great pre-park quick breakfast, especially if you like Beignets. Also, there are pastry carts in CA and in DL where you can grab a croissant or something when you get there and then just eat it on the go. We were there last week, and DD and I discovered that Churros actually make a great breakfast food. If we weren't doing a TS breakfast, we just stopped at the Churro cart by the castle first thing in the morning and ate it as we walked to whatever we wanted to do first. I'm pretty sure that is going to be our new go to quick breakfast at DLR. DH isn't a churro fan, so he headed off to the pastry cart on the other side of the hub for a chocolate croissant.
As far as in park breakfasts, if you like characters, Minnie's is our absolute favorite. We love the large amount of characters and the variety of characters. We also did Ariel's Grotto breakfast last week for the first time (we have always done lunch there in the past, but do not like the lunch food since the menu change last year) and we thought the food there was great!