Yes?
Green Jello/ Green Jelly
Correct, I’ll give you the last one without the umlauts. 
Any truth to the assertion I heard that the umlaut over the y (ÿ) gave the y an “o” sound, so that despite the spelling change, it was still pronounced “Jello”?
82. This band, already the answer to another clue in this thread, originally named itself after a NBA player, but had to change names when they learned the player’s name was trademarked.
- Pearl Jam was at one time called Mookie Blaylock.
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This band got its name from a grocery store often visited for snacks during recording sessions.
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This band was named after a song on a Muddy Waters album.
Rolling Stones!
- Rolling Stones
Yes!
- The members of this country act, while still performing in bars and restaurant lounges, decided to shorten their name to its current form after too many instances of being mistaken for the dinner special rather than the entertainment.
And only 84 bands in!
- And continuing the obvious, this band’s name was inspired by Buddy Holly’s Crickets.
- Beatles
- Speaking of dessert, this English band is named after one.
Humble Pie? (guess)
Nope. An actual real dessert, not that I haven’t deserved humble pie before.
Big Star?
Correct.
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This band took its name from the military and commercial aviation radio voice acronym for “Will Comply.”
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This “prehistoric” band had to add “Jr.” to its name because the original was already taken.
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Wilco
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Dinosaur Jr.
Yeah, President, I figured those would go pretty fast.
Yes, well… 
A relatively tough one, but one I’m amused by:
- In trying to decide on a name, this band allegedly took psychedelic mushrooms. When they recovered from the trip, their notepad only had these words legible.
Nickelback was named after the amount of change Mike Kroeger often gave when he worked at Starbucks. Here’s one cite.