While being interviewed on The Movie Crypt podcast, director James Gunn talked a bit about which Marvel characters he was interested in using in GUARDIANS OF THE GALAXY, but couldn't due to legal reasons. Gunn says Bug (also known as "Galactic Warrior") and the cyborg Rom: Spaceknight probably would have made it into the film if Marvel owned the rights, as well as the reptilian alien species the Badoon.
There's characters that I've been interested in that I'm not allowed to use but I won't go so far as to say I definitely would have had them. There was a really good chance Bug was going to show up in the first movie but we do not own him… but, anyway, that was going to happen, perhaps. Listen, I really love Rom: Spaceknight, as everyone at Marvel knows because they've given me Rom stuff… but we don't own Rom. I would love for Rom: Spaceknight to show up because I love his story, I love the way he looks, I love everything about him…There are other characters, but basically, some characters we can work around and we can use. Listen, I wanted to use the Badoon, but the Badoon we don't own… they're really interesting. They would be like the cannon fodder guys who were like the Sakaaran in my movie… I wrote them as Badoon but I just did a search-replace-Sakaaran when I found out we didn't have Badoon. It was strangely late in the process when I found that out. They were designed as Badoon.
It's not like Bug, Rom and the Badoon are well-known Marvel characters, so I doubt most of you are disappointed they didn't appear in GUARDIANS OF THE GALAXY. Although it would have been awesome to see what James Gunn would have done with them, I'm pretty sure Marvel still has plenty of other characters Gunn will be able to use in the sequel.
GUARDIANS OF THE GALAXY 2 is scheduled to open on May 5, 2017.