With all versions of Xpress Pro less than v.5, you need a Mojo to output back to NTSC. This is because it adds the 2:3 insertion to create a true NTSC 59.94 field signal. On version v.5 and later, this is done in the host. So yes, you need a Mojo to output to NTSC or export a QT ref into After Effects, render in a 2:3 pulldown and import back into a 30i project.
If you created a 30i project (29.97i) you can certainly edit in a matchback mod. Make sure you selected “Matchback” when creating the project. Many films have been done this way. A conform in DS or linear suite will need to be done via EDL. EDL’s as with cutlists will be adjusted +/-1 frame at any one cut point to maintain overall audio sync.
Michael