Sorry if I was unclear: he has a chip in his current passport, and he has visited on a previous ESTA.-I meant that on his last visit with ESTA, it was an older passport without a chip (back in 2013). Didn't know if this would make any difference (as I figured these e-gates might be comparing to something on the chip back then).
So it sounds like we'll both be able to use these, which will be really handy - I am surprised that CBP doesn't require a face-to-face chat for non-GE people! What exactly is the difference between GE and these kiosks then, or are the kiosks more in-depth than the quick passport and eye/photo scan that the European ones do?
GE is not an option because apparently the interview can only be done in the US (or Canada/Qatar) - and we'll only be there next for this visit!
And yes, you are correct re being same-sex. We'll just go in separate queues I guess, and whoever gets through first can sort the customs progress. Will certainly be begging for assistance if things are looking tight!