Here's my guess of the 67 character line-up:
1. Iron Man
2. Captain America
3. Thor
4. Hulk
5. Hawkeye
6. Black Widow
7. Scarlett Witch
8. Star Lord
9. Groot
10. Rocket Racoon
11. Drax
12. Gamora
13. Nick Fury
14. Ant-Man
15. Black Panther
16. Doctor Strange
17. Spider-Man
18. Captain Marvel
19. Wasp
20. Hank Pym
21. DareDevil
22. Jessica Jones
23. Luke Cage
24. Iron Fist
25. The Punisher
26. Phil Coulson
27. Daisy Johnson/Quake
28. Melinda May
29. Leo Fitz
30. Jemma Simmons
31. Mack
32. Daniel Sousa
33. Vision
34. Nebula
35. Loki
36. The Grandmaster
37. The Vulture/Norman Osborn (depending on which Michael Keataon plays)
38. The Falcon
39. War Machine
40. The Winter Soldier
41. Sif
42. Aunt May
43. The Ancient One
44. Everett Ross
45. Odin
46. Pepper Potts
47. Sharon Carter
48. Heimdall
49. Maria Hill
50. Red Skull
51. Ulysses Klaue
52. Happy Hogan
53. Bobbi Morse/Mockingbird
54. Wonder Man
55. Jasper Sitwell
56. General Ross
57. The Collector
58. Korath
59. Zemo
60.The Watcher (played by Stan Lee)
61.Silver Surfer (After a confirmation that Marvel have bought the Fantastic Four rights back)
62. Mister Fantastic (See Silver Surfer, surprise at the end)
63.Invisible Woman (See Silver Surfer, surprise at the end)
64. Human Torch (See Silver Surfer, surprise at the end)
65.The Thing (See Silver Surfer, surprise at the end)
66. Thanos
67. Death