VGFacts

As part of Dead Rising 4: Frank's Big Package, Capcom Heroes is a mode included in the game where Frank can play as Capcom characters that pay homage to other capcom games. They can be unlocked as followed:

Dead Rising 4 Capcom Heroes - All Costumes And Shadow Costumes Showcase Gameplay - YouTube

Classic Frank (Dead Rising)
Dante (Devil May Cry series)
X (Mega Man X)
Ryu (Street Fighter V)
Cammy (Street Fighter series)
Viewtiful Joe (Viewtiful Joe series)
Mecha-Zangief (Ultimate Street Fighter IV)
M. Bison (Street Fighter series) 
Adam the Clown (Dead Rising)
Arthur (Ghost N' Globlins)
Bass (Mega Man series)
Morrigan (Darkstalkers)
Sissel (Ghost Trick Phantom Detective)
Zombie Frank (Frank Rising DLC)
Jill Valentine (Resident Evil 3)
Amaterasu (Okami)
Akuma (Street Fighter)


There are posters in the game when playing Capcom Heroes: 

Dead Rising 4 | Capcom Heroes - All Video Game Poster Locations | Xbox One - YouTube

Dead Rising
Cadillacs and Dinosaurs
Street Fighter
Viewtiful Joe
Darkstalkers
Devil May Cry 4: Special Edition
Zack and Wiki
Dino Crisis 3
Rival Schools: United by Fate
Okami
Lost Planet 3
Resident Evil 7: Biohazard
Phoenix Wright Ace Attorney: Spirit of Justice
Super Puzzle Fighter 2 Turbo


There are a few Capcom costumes that can be found within the game if playing story mode:
Dead Rising 4 All Outfits Showcase - YouTube

Mechanic's Outfit (Nick Ramos from Dead Rising 3)
Businesswoman Outfit (Rebecca Chang from Dead Rising 2)
Bass (Mega Man series)
Zero (Mega Man X series)
Captain Commando (Captain Commando)
Vega (Street Fighter series)
Morrigan (Darkstalkers)
Akuma (Street Fighter)
Haggar (Final Fight)

aside from these costumes, the mechanic's outfit and businesswoman outfit are references to both Nick Ramos and Rebecca Chang, who appear in Dead Rising 2 and Dead Rising 3. 


There are few locations that include items and other references to Capcom games upon entering them:

Easter Eggs (Dead Rising 4) | Dead Rising Wiki | Fandom

Tetro's Comics & Collectibles located in Old Town

Super Punch Comics located in the Willamette Megaplex Mall

Ja-POP! located in Kiichiro Plaza

The Prawp Family home located in West Ridge

King Hiro Arcade located in Kiichiro Plaza

The Jill Sandwich trial, which requires Frank to eat a sandwich equipped with the Jill Valentine costume, is a reference to the infamous line said by Barry Burton in Resident Evil where he saves Jill and says the exact same thing. 




(skip to 0:33)


The Zero Exo Suit can be unlocked by beating the game, which strikingly resembles Zero from the Mega Man X series. Additionally, a giant Zero Mech can be found in Kiichiro Plaza.