I think your Pearl Jam story is the one that Vedder told to a credulous journo who swallowed it hook, line and sinker. The singer himself admitted to
Rolling Stone that is was "total bull****".
The truth, mentioned in the article, is somewhat more prosaic: they were Christened "Pearl" by bassist Jeff Ament & added the second word after a Neil Young gig were he played several 15-20 minute jams.
Of band omitted from your list the godlike
Thin White Rope were named after a William Burroughs's description of semen from
The Naked Lunch, perennial CW favs
The Decemberists take theirs from the 1825 abortive Decembrist Uprising in Russia &, sadly, rumours Bury's finest
Elbow took their moniker from nickname of Pakistan off-spinner Saeed Ajmal are apocryphal.They actually used a line from Dennis Potter's telly series
The Singing Dectective, wherein Michael Gambon says "elbow" is the most sensuous word in English because of the way it feels to say.
