Head up to the second floor of the Avengers mansion, into Gwenpool's room on the left (you must complete the initial tutorial before the door becomes unlocked). In the room you will see a computer, head over and input the following codes to unlock these bonuses.
Antman BCR7QJ
Baby Groot QG3VH9
Captain Britain M68P3L
Crimson Dynamo CDS278
Darkstar S947TP
Giant-Man (Hank Pym) GAVK9R
Grandmaster (Ragnarok) LBYT59
Green Goblin XG7SAL
Hawkeye G6K2VM
Hellcow NCMJU4
Hulkling 5G7HFS
Loki JDNQMV
Maestro HCE926
Militant UUTZNC
Misty Knight BK9B3Y
Scarlet Spider JD9GQA
Songbird D6LJ4P
Spider-Man UKRMADXF
Spider-Woman CW9BRS
Vision (Civil War) 4U9DAT
Vulture (Homecoming) 7KDY3L
Winter Soldier 8KD3F6
