Overall, Gotham has some similarities to the comics, but it also makes significant changes to characters and plotlines to make it more unique for the TV series. For example, some characters' personalities and backstories are altered.
In most cases, Gotham is canon to comics. It incorporates many elements and storylines from the comic universe, maintaining consistency and respecting the source material. However, there might be some creative interpretations or minor deviations for the sake of the TV show's narrative.
Definitely. Gotham takes inspiration from the DC Comics universe and develops stories centered around the city and its various characters related to Batman's lore. The show incorporates elements and characters familiar to DC Comics fans.