Yeah, for me, he’s #1 of the folks on the list. But in terms of general public? Doubt it. McCartney for sure. Dylan probably #2. Even if you don’t care for him (I can’t get into his work), he’s a cultural superstar. I’m not even sure most people would even know who Brian Wilson is.
I thought Paul McCartney was already dead. I know he was in that one band before Wings.
Dylan’s six albums from The Freewheeling Bob Dylan to Blonde on Blonde may be the best six-album run ever. And they all came out within a 37-month period. We’ll never see anything like that again. If rock has a genius he’s it.
The Beatles were in awe of Dylan. They changed their music because of Dylan. They competed with Wilson but didn’t change their thinking because of him.
None of that matters. The Beatles tower over everyone from that period. McCartney’s death will stop the world. Not that’s he’s number one right now. If Taylor Swift died, the internet would melt down. Cats and dogs would hug. Time itself may stop. But she’s not 81 years old.
She can’t DIE! You monster! [runs away sobbing]
Well said.
Your OP asked about who’d make the biggest splash on the way out of the building. I bet the answer differs a bunch whether we’re talking about a splash among the whole world (or whole USA), or among the folks passionate about 1960s rock music specifically.
I’m much more in the former group. I was age 2-12 in the 1960s. I listened to pop / rock music, but was never a fan or afficianado or obsessed with any of it.
On that very much non-expert basis I vote the two Beatles, and Dylan in that order. Regardless of McCartney’s & Starr’s order of death, the Last Beatle will be a bigger deal than was the Next-to-Last Beatle.
I also think the rock/pop distinction starts to bite real early. The experts / afficianados know the difference. The top 40 schlubs like me? Not so much. Why’s Jim Croce not on your list? (Besides having been dead now for 50 years? 
) Not a rocker. But certainly an important figure then.
To me he is the last of the original blues legends. I’m not sure how big a splash he will make with the general population, but certainly a huge one with blues lovers.
A lot have moved on in recent years:
It’s almost like that group is really two groups - and I don’t think Brian Wilson , Frankie Valli and Diana Ross are in the same group as the others.Not because they weren’t popular in their time, not because they weren’t influential. But because they didn’t stay well-known ( that’s not really what I mean, but I’m having trouble describing it. ) My 33 year old son might have heard of Brian Wilson but I’m certain he’s never heard of Diana Ross or Frankie Valli . Although I know a few of my 60 ish peers have seen Jersey Boys , their reaction to Valli’s death would be surprise that he’s still alive. And I don’t think there will be a big splash regarding someone who is really only well-known/popular among the 70 + group
Ringo (and his wife Barbara) went through rehab for alcohol abuse in the late '80s, and the sense I have is that they both really cleaned up their acts from that point forward. Given that he’s 83 (he’s a couple of weeks younger than my mother), he looks great, and seems to be in excellent health.
Here’s a picture of him and Joe Walsh, from an appearance he made last week, on his birthday. He doesn’t look like an octogenarian. 
Despite having been the oldest of the Beatles, my money is on him being the last one standing.
Damn. That’s some Picture of Dorian Gray shit right there.
Add three to your list, to make thirteen, with a couple extra for alternates, and you have a fine DeathPool list. I may save it for this December.
Elvis
What? You didn’t buy that fake news…
No question about it.
Decades ago I thought Ringo would be one of the first to go, as he had a big problem with alcohol for quite a few years. But he got himself sober, and in shape, and he’s still touring constantly. He does not look anywhere near his age.
McCartney looked immortal for a long time, retaining his ‘boyish’ looks well into his 50’s. Now he’s looking older, but still fit and still performing.
Of all the people on that list, I’d probably pick McCartney and Ringo as the two who are likely to be alive after the others have passed. Maybe not live to the oldest age; Frankie Valli is already 89 and still going. However, Paul has apparently had recent mental health issues and some drinking issues, while Ringo survived two bouts of Covid-19 in the last two years.
I agree that if anyone should be taken off that list, it’s Valli. When he passes I think it will be a small story. Many of his fans are already dead, and he hasn’t been a cultural factor for 50 years. Valli was already considered an ‘oldies’ act in the 70’s when he had a resurgence with “Oh What a Night”, “Grease” and “My Eyes Adored You”. Then he faded back into oldies territory soon after.
We all know why you left him off: because he’s obviously never going to die!
I’m one step behind you.
Twenty years ago, when he was married to Heather Mills (which, as it later came out, was an acrimonious marriage, to say the least), he started to suddenly look old to me; I now suspect that the stress of that marriage had a role in that. After he got out of that relationship, I think he did start to look better.
For me, Jeff Beck’s death has already eclipsed everyone on your list except for Dylan and Jagger.
And that’s going to differ for each person. I’d propose a world-wide poll, but does anyone know what their subjective list would be when someone dies?
I know that if I made a list, I’d end up being surprised by how much the death of someone not on my list affected me. It’s happened to me, both ways. People whose deaths I assumed would affect me… didn’t (Ever since Cream, I was a huge Jack Bruce fan, but oh, well… as a prog fan, same with Greg Lake, Tony Banks, Keith Emerson and Chris Squire).
And vice-versa (Don’t listen to much blues, but really miss B.B.King; and I hate banjo, but Pete Seeger was so much more).
The deaths of Bowie, and the other Davy Jones, Chris Cornell, Dr.John, Neil Innes and George Martin would not have been on my list, but hit me hard.
Whichever one gets killed by murder hornets.
That is, the way in which they die could make a difference. But if we don’t worry about that…
The list given in the OP is not bad at all—not unassailable, but there’s nothing about it that stands out as obviously wrong to me. I agree that Stevie Wonder at least deserves consideration. Maybe John Fogerty does too. Personally, either of the Davies brothers would hit me hard, but they’re probably not a bigger deal to the world at large than the names on your list.
Some honorable mentions (that haven’t been mentioned):
Rod Stewart
Bob Weir
John Densmore and Robby Krieger
And although not entirely meeting the criteria of the thread, two more icons:
Tony Bennet
Berry Gordy