As a coda to the puzzle, here come all the explanations. The solution can be viewed in this image. A clue-explainer video follows, and then some words on the theme.
(Sorry, slightly hissy audio on this one.)
This grid is a pangram. Written in April.
There were three slight hints (the extraneous “i” not being one of them – oops) to the theme in my tweet..
— The Void ザ・ヴォイド #PR! #CovidIsAirborne 💙 (@TheVoidTLMB) November 1, 2021
… since “Friends” and “In The Evening” are songs, and “Presence” is an album, by Led Zeppelin. Their members were John Paul JON_ES, John BON_HAM, Jimmy P_AGE, and Robert PLANT. SWANSONG was their record label, and OZONE BABY, and IMMIGRANT SONG were two more of their songs, while another was “D’yer Mak’er” (See 2d). Some people have teased me about making references to “obscure bands” in my puzzles, so I thought I’d have a theme of the band who were the biggest on the planet (in the 70s). Famous enough for you, folks? 😉