My experience with hatchery birds of your breeds...
buff Orpingtons.....decent layers, nice docile, calm birds that tolerate handling or being pets. Get along well with other birds. Tend to go broody. Larger birds so they do eat more, eggs are large though.
speckled Sussex....pretty to look at. Average layers of medium eggs, I was not thrilled with the amount or size of eggs. Larger birds so ate a lot. Middle of the road personality wise. never caused issues in the flock, not especially friendly or flighty.
Silkies.....cute little things, don't always do well with dual purpose birds as they tend to get picked on. Great pets, docile, calm. Okay layers, tend to go broody a lot. Feathered feet mean you'll need to avoid mud or wet conditions.
Cornish...I'm thinking you mean Dark Cornish, not Cornish cross. Good broody mommas, poor layers. Eat a ton. Fairly assertive in the flock and may pick on more docile breeds if space is getting tight or the weather is bad and the birds are confined. Supposed to be great at free ranging, I never had the opportunity.
Easter eggers.....I'm biased towards these birds. They were my favorite from early childhood. I love the visual diversity of feather colors you get, and the beautiful egg basket. Plus, who doesn't love puffy cheeks?!? I've never had issues with them being aggressive, they've always gotten along nicely with the rest of the flock and mine have been great layers. They're lighter-bodied birds so they don't eat as much for the amount of eggs, in my experience.
Don't limit yourself to one breed
. Get a diverse flock, try out different breeds. Some may look great on paper, but in person you just don't like them. Some you think you'd never like, you get one and she just wins your heart.