X-rays recently revealed a slight curvature of my 6 year olds spine. doctor and specialist said that the curvature is so slight we should wait a year and see if theres change. my question is, should she avoid picking up her younger siblings for now?

Not particularly: Mild curvatures are relatively common and there is no reason to limit the kids activities. I suspect there will be little change in any curve until she hits the pre-teen years. These curves, like the new spring growth of a plant may bend more with rapid growth. Surveillance during her rapid growth phase will either show she needs treatment or not. Sometimes a slight curve will disappear.