I was on cleared domestic, even though expired.

May I ask, what is "cleared domestic"? Did you mean to say you had TSA PreCheck?

Just out of curiosity, did you ask if they would interview you first, then scan your passport at a later date, not as a walk in?

How can one learn where their renewal application stands? They tell you to look at the "dashboard," but I see nothing there about where I stand in the cue, only that they received my $100 approximately 6 weeks ago. And how does one learn that they can come in for their interview, does on get an e-mail to that effect or must one keep going to that dashboard to look for notice there? Am I overlooking some useful information that is there to see?

Any idea how long the delay is at present in processing these renewals? How long was that delay before the government shutdown, but I gather was responsible for a big backlog at present?

With the interviews, is there an accommodations of walk-ins or one must always have an appointment? Not possible to just drop-in when killing time at the airport?

You may or may not receive an email. It is best to log in every so often to see if there is a status change.
No.
No one knows.
You can make an appointment online once you receive your conditional approval. You may receive a final approval without an interview. https://www.flyertalk.com/forum/showthread.php?t=1364352&referrerid=22732 is available at certain centers.

DownUnderFlyer applied for his/her renewal in June 2018, s/he still has not received a conditional or final approval yet.

Based on comments here, they seem to be doing them in order and up to at least Mid december, except for the odd exception of course. I think you have a bit longer to wait if it's only been 6 weeks.

I applied for my (2nd) GE renewal on 11/19/18 (T-364) [long before shutdown] and I got an email on 2/5/19 that "my status has changed"--I was approved with NO interview required. From other posts in this thread, they are NOT sending everyone emails.
Some locations (from a quick search) have lots of openings, for JFK one could have scheduled an appointment today(!) as well as every day way out in the future.

Moderator's Note
 

For indexing and future search purposes, Enrollment on Arrival - including when interviews are required for Global Entry renewals - is discussed in following thread:
TWA884
Travel Safety/Security co-moderator

Whoops, thanks.

I applied for renewal 12/23, have a govt security clearance and still not approved yet.
SO applied for renewal 2/17 approved 2/24 without new interview

so who knows how this works and incredibly frustrating given I've now had 2 full trips without pre-check. Wonder if its even worse when one has a govt security clearance given the posts on this board.

Did you renew your Global Entry before expiration date?

As repeatedly demonstrated in this and other threads, "first in, first out" is NOT how GE renewals are processed. Rather, it is essentially random that a renewal takes as little as 1 week vs up to 6 months.

Since renewals can be submitted up to 364 days prior to expiration, skip the anxiety and put a note on your calendar TODAY to renew one day after your birthday - the year prior to GE expiration.