I just thought this information might be interesting, if not actually useful, because I remember the question coming up before and there being different answers.
I can confirm that hosts can continue to earn Superhost status with no active listings at all. My only listing has been unlisted (not snoozed) since April 7.
The only stay I hosted for the quarter started March 29 and ended April 7, so there is one review for the quarter, but I don’t think this matters. I imagine there are other hosts that unlisted in March 2020 and have no reservations/reviews for the quarter that can confirm or deny this.
I suppose in January, I’ll get another Superhost four-quarters-in-a-row $100 voucher that I won’t be able to use.