Your ideas are good ones. Thank you.As an avid reader I would suggest not making the main character bi-sexual. He's a Black male detective. That is enough for the reader to follow.
Walter Mosely, a Black mystery writer, is the detective in his novels. You might want to skim through one of his early novels.
If you want to be inclusive, maybe make a character close to the main character bisexual. Tobis(sp) will be to busy with detective work to focus on who he's sexing (readers might close the book).
Since you do not know much about the Black race, why not include a character like yourself in the novel. Maybe Tobis friend or girlfriend or nosey neighbor. That way you can learn as you write. (Tobis gets annoyed with your interest in Black people, questions), but he likes you as a person and keeps you around.
You could describe identifying characters as you bring them in. That way race will not dominate.