Are the liners for the Systainer Tloc and Sys3 inter-compatible?

No, they are all different. Please use the Ekat spare parts drawings to view the various liners. In the menu go to; -> Workplace organisation -> Systainer/storage systems -> Systainer SORTAINER then either Systainer Gen3 or Systainer Tloc 1-5.
Scroll down to see the list of liners.