Interpreting USB-C land pattern
The "MID" in the other layout is for the mid-plate connections. The mid-plate separate the upper and lower pins and with some connectors has a metal grounding bar located on it:



You can see the metal bar located on the mid plate in the image above.

If your connector doesn't have that grounding bar, it is OK to leave those connections floating. The connections are there mostly for a universal insert from the manufacturer, but you can think of them as additional mechanical mount points.