Are there good stomach-toning exercises that i easily can do? i have extreme scoliosis and lordosis.

Yes: There are many, many toning exercises for the abdominal region. All of them require effort to do well, so i don't know that the word "easily" really applies. Your back problems will limit motion. Look for exercises, like Pilates for example, that use only a slight range of motion but still manage to provide significant toning. And be careful; if it hurts, ease up a bit. Don't over do.

Pelvic stabilization: Some degree of lumbar lordosis is normal. Excessive lumbar lordosis can be the result of anterior pelvic tilt which can be due to tight hamstrings. "lordosing" sports such as line in football and gymnastics can be associated with spondylolysis and spondylilithesis. Scoliosis is a lateral curvature of the spine. Stretching and back stabilization exercises are recommended. Crunches are good for abs.