5* feeders / 4* champ rewards (full list)

HoundofShadow

Archangel

Black Bolt ———————————— Medusa

Black Panther —————————— Black Panther

Black Widow ——————————— Black Widow

Cable

Captain America (First Avenger) —— Peggy Carter

Captain America (IW) ——————— Winter Soldier

Captain Marvel —————————— Captain Marvel

Daredevil ————————————— Kingpin

Doctor Doom

Doctor Octopus —————————— Carnage

Doctor Strange —————————— Mordo

Gambit

Ghost Rider ———————————— Ghost Rider

Green Goblin ——————————— Sandman

Hawkeye ————————————— Kate Bishop

Hela

Iceman

Iron Man ————————————— War Machine

Jean Grey ———————————— Jubilee

Jessica Jones ——————————— America Chavez

Kingpin —————————— Miles Morales

Kitty Pryde

Loki ———————————————The Hulk (Main Event)

Okoye —————————————— Shuri

Prof X

Rescue

Silver Surfer ———————————— Mr. Fantastic

Spider-Man (Back in Black) ————— Spider-Man (Infinity War)

Spider-Man (Peter Parker) ————— Vulture

Star-Lord ————————————— Drax

Storm 

Thanos —————————————— Gamora

The Hulk

Thor ——————————————— Valkyrie

Wasp ——————————————— Ant-Man

Wolverine ————————————— Wolverine

Note: 37 5-star characters. 11 5-stars don't have feeders yet.

turianbrandy

They're taking waaaay too long to update/complete this on the devs end.

4*Deadpool should give Cable

4*Cyclops should give Prof X

Coulson should give Rescue

Rogue should give Gambit

4*Iceman should give 5*Iceman

Domino should give Archangel

Hulkbuster should give Hulk

Invisible Woman should give Doom

Magik should give Kitty Pryde

Jane Foster should give Hela
Nightcrawler should give Storm

Zzzz what gives devs...

111MCH111

With the introduction of shards, all your questions are answered. Differently, example: Emma Frost feeds Kitty