though "tea" dying or creamy white would look more vintage, if it is not inkeeping with her current color scheme, you have to stick with the pure white and red. Batting and quilting will warm it up a bit.
I'm wondering if maybe the red is a little bright. Is everyting in her room the "true" red, or is it a bit creamier? what would happen with a small red and white print with a red background?
I think your blocks are beautiful!!!
One thought about making it reversible (which I think is a great idea) is to keep the pattern the same on the back, just use different fabrics.
If you change the pattern then you are limiting yourself to quilting an all-over. If you want to play up the quilting in your red and white blocks, the pattern on the osther side must relate to the quilting.
(ASK ME HOW I KNOW!!)
Good luck!