If you like the cottage feel and if you have a lot of backyard space, don't forget about lilac bushes!
I don't know that I have placement recommendations for you because one thing builds on another, so landscaping, to me, feels like something I do all at once, more or less. I wish I could be of more help. If I think of very definitive suggestions, I'll post more later.
I can say, however, that sweet alyssum lend themselves well to a cottage-y feel...they look very lacy and smell heavenly when you run your hands through a bunch of them. They will self-seed somewhat, though, so be prepared for that. (I planted them last year and they are a little too lacy for my design scheme, but they kept coming back this year so I just let them be for now.) They would be great between other flowers as sort of a groundcover and a nice, white backdrop to flowers of other colors.
