Okay, update on our "GE to NEXUS" process.
My GE expired in February, my wife's and my son's GE are to expire in 3 months. We applied for NEXUS in February with a few days/a week in between the applications (didn't have time to do all at once).
~40 days after my application I got my Approved notice and then a week later got my NEXUS card - no interview!
Within a similar timeframe my son and my wife got their "Conditional Approval" notifications and we scheduled their interviews for later this month.
I have no clue what led to my experience of getting a NEXUS card without an interview - the only difference between me and my wife was that by the time of approval, my GE was technically already expired, so maybe they wanted to expedite this so that I could use my benefits with as little interruption as possible?! Don't know if that mattered at all or not, but I used my GE extensively for 2 or 3 years having 1-2 trips a month on average.