Can a woman with dextrocardia situs inversus with no atrial wall still have uncomplicated pregnancy/labor/delivery/postpartum course?

Probably. Dextrocardia and situs inversus will not cause any issues, although things may be backwards. However, I am not sure what you mean by no atrial wall. This could be a serious abnormality. The heart needs 4 chambers (rooms) separated by the right doors (valves or pregnancy could have some difficulties. Please provide more information.
Hopefully... If you have a congenital cardiac defect known as left atrial isomerism and heterotaxy, you have a very high risk for pregnancy complications and should consult with a pediatric cardiologist expert in congenital heart disease and a maternal-fetal medicine expert to devise an optimal pregnancy plan. Arrhythmias and heart failure can be a concern and you should avoid unplanned pregnancies.