Bathroom Curtain and Linen Color Advice?

Choose any colors in the wallpaper

You can't go wrong with a mauve-y pink or periwinkle blue to add a little more interest and not be all match match.

Rug I would do cream or ivory.
For the bathroom curtains I would go with a navy and towels pink.

I'd choose cream or ivory for the curtain, Lighter colored curtains tend to make a room look brighter and more spacious. I'd draw out the rose and navy from the wallpaper with towels and a rug in one of those colors.

Pink or cream

I like a pale pink or a pale green, I think those would go great