I know according to a recent release that External Tools are now hidden:
External tool (LTI) submissions are better supported in Assignment Enhancements. Additionally, the placement of the External Tool buttons have been adjusted. Instead of displaying within the File Uploads option, installed tools for a course display as buttons next to all other submission types. If an assignment includes multiple tools, the External Tool options may be accessed via the More button, which we have reintroduced with this deploy to eliminate the confusion and clutter associated with many tools being available for student use.
Would it be possible to keep it consistent with the RCE and allow districts to choose two tools to display with buttons instead of hiding them all?