Both of those are correct with the addition that they backdoor pilots were to be for superhero shows where they were the lead. Thor was hoped to spin out of Incredible Hulk Returns, Daredevil out of  Trial of the Incredible Hulk, Painkiller out of Black Lightning, Mia Smoak's Green Arrow and the Canaries out of Arrow. Some see Aquaman's first appearance in Smallville as such, but I'm dubious since there was an actual failed pilot for him.

Troma has admitted to not realizing Marisa Tomei was in one of their movies until she was asked what her first movie was and she replied the Toxic Avenger.
 

6.  DC Comics characters whose names all start with "Captain".

Final clues. Will reveal the answers some time tomorrow Pacific time.

1. George W. Bush, Kim Jung un. Joe Pantoliano, Jennifer Tilly, Meg Tilly, Bill Murray
They share a specific difference. That is to say, most other living famous people do not share this. For half of these the link is TV, the other half movies.
In the second second above I actually reveal half the answer. If you compare that to the first sentence you may be able to extrapolate the answer.
Think state of being.

3. Unbreakable, Pulp Fiction, Terror Firmer, Iron Man, The Expendables, Rocky II, Star Trek IV: The Voyage Home, Star Trek  V: The Final Frontier, Iron Man 2, Unforgiven
The connection is roles. I'm thinking two kinds of roles but there might be more. Think of the camera.
What's behind is as important as what's in front.

7. Sonny Bonds, Roger Wilco, Larry Laffer, Graham, Rosella
The link is not related to one of the media normally covered in these questions but it's still part of pop culture. All of these characters first appeared in the 1980s, but that's not the link I'm looking for.
The above characters are respectively a police officer, a space janitor, a lounge lizard, and two members of royalty.
All of the above have embarked on quests tailored to their characters.
The medium is PC games.
Larry Laffer is also known as Leisure Suit Larry.

9. Danny Seagren, Jim Boyd, Bill Cosby, Irene Cara, Luis Avalos, Skip Hinnant, Judy Graubart, Hattie Winston, Rita Moreno, Morgan Freeman
The link is TV related. The link spans many years within a specific decade.
The decade is the 1970s.

10. I Love You to Death, Milkshake, Samantha, Liberation, The Sound of the City, Magic Night, titular song, YMCA
All of these are songs but it's not enough to just name the singer/s. The link was the first to win a specific award that continues to this day.
Think movie.
 

3 is correct, and with speaking lines, not just Hitchcock style cameos.

The remaining answers:

1. George W. Bush, Kim Jung un. Joe Pantoliano, Jennifer Tilly, Meg Tilly, Bill Murray
They share a specific difference. That is to say, most other living famous people do not share this. For half of these the link is TV, the other half movies.
In the second second above I actually reveal half the answer. If you compare that to the first sentence you may be able to extrapolate the answer.
Think state of being.

All of the above are currently alive in the real world but dead in at least one fictional reality

George W. Bush
Movie: Not really a spoiler in this instance but just in case:

Death of a President

Cause of Death:

Shot by sniper

Kim Jung un
Movie:

The Interview

Cause of Death:

While attempting in a helicopter to kill Dave Skylark and his allies in a truck below, Skylark fires a missile at the helicopter, killing him

Joe Pantoliano
TV Series:

Chucky

Episode:

Season 2 Episode 4 Death on Denial

Cause of Death:

Realizing that Joe loves "Jennifer Tilly" (actually Tiffany Valentine), a jealous Gina Gershon shoots him to death

Jennifer Tilly
TV Series:

Chucky

Episode:

Season 2 Episode 7 Goin' to the Chapel

Cause of Death:

Tiffany Valentine plans to trade places with Jennifer, putting herself in doll form and Jennifer back in her original body, meaning that Jennifer will serve time for Tiffany's crimes while Tiffany is free. jennifer runs into traffic and is run over by a semi-truck.

Meg Tilly
TV Series:

Chucky

Episode:

Season 2 Episode 5 Doll on Doll

Cause of Death:

Meg discovers her sister Jennifer trapped in doll form. Jennifer tries to enlist her aid, but Tiffany Valentine, in Jennifer's original body, stabs Meg to death with a nail file

Bill Murray
Movie:

Zombieland

Cause of Death:

Despite knowing they're zombie hunters, Bill puts on zombie makeup and tries to scare Little Rock and Columbius. Columbius shoots him to death

7. Sonny Bonds, Roger Wilco, Larry Laffer, Graham, Rosella
The link is not related to one of the media normally covered in these questions but it's still part of pop culture. All of these characters first appeared in the 1980s, but that's not the link I'm looking for.
The above characters are respectively a police officer, a space janitor, a lounge lizard, and two members of royalty.
All of the above have embarked on quests tailored to their characters.
The medium is PC games.
Larry Laffer is also known as Leisure Suit Larry.

All of the above were lead characters in multiple games during the classic era of Sierra adventure games, respectively: Police Quest, Space Quest, Leisure Suit Larry, King's Quest, King's Quest again.

9. Danny Seagren, Jim Boyd, Bill Cosby, Irene Cara, Luis Avalos, Skip Hinnant, Judy Graubart, Hattie Winston, Rita Moreno, Morgan Freeman
The link is TV related. The link spans many years within a specific decade.
The decade is the 1970s.

All were regulars on the Electric Company. Notable characters include respectively, Spider-Man, J. Arthur Crank, Marko the Magician, Short Circus performer. Dr Doolats, Fargo North: Decoder, Jennifer of the Jungle, Valerie the Librarian, The Director, Easy Reader

10. I Love You to Death, Milkshake, Samantha, Liberation, The Sound of the City, Magic Night, titular song, YMCA
All of these are songs but it's not enough to just name the singer/s. The link was the first to win a specific award that continues to this day.
Think movie.
 
All were songs in Can't Stop the Music, the first movie to win a Razzie for Worst Picture. Actually nowadays it makes for an interesting time capsule for the look and colours of its era.

 

#6 were all sequel novels not written by the original authors. Not sure if you're looking for something more specific than that.

#12: the second word of film titles where the first word is a color.

# 9 were all cast members of the 80's one-season wonder "Misfits of Science"

I made an error in the first question so I'll correct it and add more clues while I'm at it.
1. Annie, O'Neil, Moone, Hopper
2. kills plants, causes amnesia, varies, kills specific artificial beings
3. carrots, peanuts, spinach, bananas
4. Deadboy, Friend Computer, Karl Ferenc Skorpios, Lorelei (Laura Lee Masters)
5. Microwoman, Web Woman, Moray, Isis
7. Venus the Flying Trap, Hasty Pudding, Plastic Man, The Monarch
8. The End, Backwards, Emohawk, The Beginning
10. Alley, Destroyer, Phoenix, Beast
11. Sleeper, Puppetman, Demise, Golden Boy

 

Adding once more to each category where possible and/or expanding on existing listings. After this I'll switch to other clues. Some like 11 I could go on for quite a while yet, but others are getting tougher to add to.
1. Annie, Eddie, O'Neil, Parker, Moone, Hopper
2. kills specific humanoid aliens, causes amnesia/removes abilities of same, varies for same, kills plants, kills specific artificial beings, gives beings powers
3. carrots (at least two instances), peanuts, spinach, bananas, cereal
4. Deadboy, Friend Computer, Karl Ferenc Skorpios, Lorelei (Laura Lee Masters), Morty Tortoise, Power Master (Richard Monroe)
5. Microwoman, Web Woman, Moray, Isis, Batgirl
Can't really add to this one; even Batgirl and arguably Isis tweaked my original idea a little
7. Venus the Flying Trap, Hasty Pudding, Plastic Man, The Monarch, Cometeer, Worm Man
8. The End, Backwards, Emohawk, The Beginning, Back to Reality, Future Echoes
10. Alley, Destroyer, Phoenix, Beast, Rider, Man
11. Sleeper, Puppetman, Demise, Golden Boy, Gimli, Mack the Knife