Everything you've bought there is sun-loving. The begonias and petunias will manage in the partial shade bed.
I second odd numbers, either of actual plants or groups, in uneven shaped groupings.
No idea what the colours are like, so reject this if they clash: what about the begonias and petunias together in two patches, that merge together like the Paisley shapes/ying yang. And then 5-7 patches of marigolds, with three groups of osteospermum inbetween?
I might add: some taller plants, or sweet peas on wigwams, to give you some height. Maybe something with sword/grass type leaves, like iris (you can get some with nice stripy leaves).
As for the shady beds, how shady, wet or dry? Maybe hostas, ferns, primrulas......