G.M.
Use them for everything - my son has one quilt in his crib, one in the car, and one as a back-up. Throw 'em in with the kiddo's wash when the rest is done - baby quilts are made to be resilient, and made to be used (and used and used).
It doesn't really matter if the fabric has been pre-washed, the quilting (or ties, depending on how they're made) will keep the quilt from shrinking or distorting.
Enjoy those quilts, and remember the love that was sewn into them - the love for the child that's using them, not the love of a perfectly decorated room to put them in!