Just came back through and have confirmed that Japanese nationals are welcome to hang out through immigration in the plebian line with their loved ones/ family members. Vice Versa is no go.
This is ridiculous. Even the US lets my Japanese wife go through the US citizens line with me. They have fingerprint readers and cameras at all stations, so they can take her prints and photo even when she goes through the US line. There is no reason why Japan can't do the same, or why they can't continue to let re-entry permit holders go through the Japanese line.
I can't believe Japan will now treat visitors even worse than the US! (And with policies that do nothing to enhance security.) What is this, a race to the bottom?