Kids are scared of rides just to get attention. They'll walk all over you if you let them. Go, and use the baby swap for the rides the 6 year old can't ride yet. He can have fun in the play ground area. If the wife doesn't care for the coasters, you can split up, husband takes the 8 year old on the thrill rides, while the wife watches the little one in the play ground areas. An 8 year old will probably make the height requirements for the coasters.