Can women who have lupus (sle) have a successful pregnancy?

Absolutely. The disease is not a reason to believe that pregnancy will be difficult. It simply puts you into a higher risk category and your ob/gyn will follow you more closely.
Yes. Sle can flare during pregnancy. A vast majority of women who become pregnant when their lupus is quiescent will do well. Your rheumatologist and OB can give the best individual advice about timing.