The Frat Pack Name Game

Will Ferell and John C. Reilly

Ricky Gervais' name for Ben in Night at the Museum

Jack Black often refers to himself as JB or Jables in interviews, also used this in Tenacious D in: The Pick of Destiny

From Starsky & Hutch, "Maury Finkle, founder of Finkle Fixtures, Biggest Lighting Fixture Chain in the Southland."
this is Ben - all the way.

Prob the most obscure question, so if you got it correct, you're likely the only one. It's from Kicking and Screaming, so the answer is Will. He's called this while waiting in line in a coffee shop.

Vince's character Jeremy Grey was referred to by this name in Wedding Crashers

From Anchorman, Paul refers to several nicknames for himself, this is the least scary.

One of the last lines of the movie Roy says his real name is Wyatt Erp, not Roy O'Bannon. Jackie, of course, responds that is a terrible name for a cowboy.

Luke appears to have been given this nickname by the cast of Old School. One of the opening scenes of the movie features a rather long, all in one shot, that Luke did perfectly in one take.

Their "handles" during the robbery scene of Bottle Rocket. Don't know where Scarecrow came from, (probably CA CAW, CA CAW!!), but Luke likes Birddog apparently, says "Bird dog him!" in Old School and X-Files episode Bad Blood.

from Idiocrasy

Luke's character Mitch Martin from Old School was referred to as The Godfather.

T for Trent in Swingers
Candyman is from Starsky & Hutch
Jeremy refers to himself as the Big Bear in Wedding Crashers
John calls Jeremy Judas and Toast in Wedding Crashers

I could have added a bunch more Owen movies here, Bottle Rocket (Jerry), The Life Aquatic (Kingsley), The Minus Man (Bob) but anyway, the answer is of course not Wedding Crashers, and Jack goes by Ned in most of School of Rock despite his name being Dewey. Luke's incorrect barcode name is tatood on his wrist in Idiocrasy, Owen never goes by his real name in Shanghai, so that would leave Envy.

From The Royal Tenenbaums

Jack's cameo on X-files was a character nicknamed Zero.

This is actually Ben shouting insulting names to Hank Azaria and William H. Macy, "Well here I thought I was with a couple of real superheroes, the Shoveller and the Blue Raja! But really, it's Lazy Boy and... and... the recliner! Lazy Boy and the Recliner!"

It's A for two reasons, BCD are all Ben/Owen exchanges while A is a Vince/Owen scene from Wedding Crashers. It is also not a "name calling" exchange as in the other three, as only Owen is hurling insults.

G-Man & K-Dog is a Meet The Parents Ben/Owen riff while Tiny & Gigantor and Blondie and Cracker Jack are Night at the Museum Ben/Owen riffs

"Definitely not Owen"
This is Micky Rooney throwing insults at Ben during Night at the Museum.

Luke in Idiocrasy

Because
Ben has played a Vince
Luke has played a Ben a couple of times
Owen and Vince have both played Lukes
Vince played a character whos real name turned out to be Jack
Vince played a Van Owen
No Steve and no Will