The initial first draft of Season 1 was finished in 2011, and clocked in at over 20 episodes.
There have been many changes in the cast from the time that the initial teaser was filmed until the end of principal photography. There have been 3 Kristens, 2 Domingos', 2 Brawn E's, and 2 Keiths.
Filming began in the summer of 2012, and once the pilot (first 4 episodes)was finished, the crew went on hiatus, unsure if they wanted to film any more episodes. After a meeting of series writers, Episodes 5-12 were plotted out and written. They contain some ideas from the initial season 1 draft, but are mostly brand new ideas.
The character of "Domingos" was initially supposed to have a fake accent in the first draft, but due to changes in the script, that storyline was axed.
Episodes 5-12 were written by Sam Platizky, Isaac Platizky, and Dan Gregory. Each writer worked on a few episodes, and then passed their scripts on the to the other writers who would make suggestions, and then the writer would take what worked and submit a final, polished draft.