Has anyone actually attempted this? Also curious if this will require another interview for PreCheck.

I did it. Enrolled in PreCheck and went to the enrollment office at DCA to finalize and pay - that took about 4 minutes.

Standalone PreCheck applications are processed by the TSA, yes, an interview is required; please refer to the following thread: The TSA PreCheck Information Thread. NEXUS (in the US) and Global Entry are managed by the CBP. Both NEXUS and Global Entry include PreCheck.

If you applied for NEXUS renewal before the expiration date, you will continue to receive all NEXUS benefits pending the final approval of the renewal application. Please refer to post number 865 in this thread.

So says the Nexus site, but it’s sounding like that the CBP may not care. Here’s anecdotal evidence of two incidences of no Pre-Check for travelers who had received conditional approval for renewals and were awaiting appointments for interviews.
Any reports from folks in the same situation who are getting Pre-Check with each flight?

Did that have any impact on your Nexus application? My Nexus expires next April, I applied for renewal a few weeks ago, got conditionally approved quickly pending an interview, but of course no appointments exist. I am flying next week, will see whether I get PreCheck. If I don't, and it is possible to get without affecting my Nexus enrollment, I would be willing to go that route.

Also - I assume that the only benefit anecdotally affected seems to be PreCheck. Global Entry continues to work, correct?

Check the TTP website for the status of your membership. Either your membership is valid (due to the various validity extensions) or it is not valid. There should be no middle ground - either valid or not valid.

My Nexus application status still says "Pending Review".

I spoke with a Canadian officer on the Nexus help line Friday afternoon and he said it appears that while Canada is extending benefits, the US may not be as people are only “conditionally approved” (or whatever the phrase is) until the renewal interviews take place.

That is incorrect!

From the US CBP National Media Release:

Data point for benefits after expiry - so far 100%.

8/19: Nexus renewal application
3/20: conditional approval
5/20 appointment cancelled.
7/20 Nexus expired
7/20 appointment cancelled
12/20 appointment cancelled
7'21 appointment cancelled
4/21 got precheck 3x, 3 separate airlines
4/21 entered US via GE line
5/21 got precheck 4th airline

Renewal request: September 23, 2020
Approved: May 13, 2021
Days to renew: 232

US Citizen / Canadian PR

No interview needed. Seems in line with others in this scenario.

Is your previous expiration date June 2021?

Yes, that's what the website says- but we're seeing anecdotal evidence (as quoted earlier) that some people are not receiving all their benefits. According to both the US and Canadian agents I spoke with today, it could be that ID in their trusted traveler record expired between the time the application was filled out and the year(s) it is taking to get an interview. I asked about this as I just got an updated license and wanted to update the expiry date in my record.

If your license or passport expires during the wait time for an interview, your record can't be updated until after your interview. Both agents said that WILL cause a problem when it comes time for PreCheck. The Canadian agent wouldn't say whether it would affect Nexus, but the US agent indicated Global Entry could be affected by an expired passport date in your record.

Applying for standalone PreCheck was offered up as a way of getting through US airport lines quickly this summer, as no one knows when Canadian borders will open for interviews. The clock is ticking - you're given a two year extension from your original expiry date (not the date of your renewal), so people with Feb 2020 expiry dates are extended only through Feb 2022 - 8.5 months from now.

applied for renewal in Oct 2020, just got notice of approval today without interview.
7 month wait