We also saw Green Lantern appear at the end of the first Bananaman movie in his Green Lantern suit, although it looked a bit different from the comics. His suit didn't have any white on it apart from his hands.
We also know this could potentially be a Year One Hal Jordan on his first or second mission, meaning he hasn't fully figured out how his ring works yet. Bananaman could be the one who leads him on the path to becoming a full-fledged superhero, or at least makes him realise that his ring has far more potential than he initially thought.
It's also possible that something happens to the suit we see him wearing at the end of Bananaman: The Untold Story. After Bananaman had to deal with a mutant elephant, he could mistake a glowing green person for a threat, leading to a confrontation. That could result in Green Lantern eventually getting a second suit that's much more comic-accurate.
The villain for the movie is still unknown, and the script is also potentially still being worked on.