There is Nickelodeon's logo on the announcement image
because title was published there? Comic is comic. It's like they said once about The Adventure Time. They can't do Bubbline canon in cartoon because it's running in countries they won't agree for this relationship, but comics are different story...
Important thing to remember is one reason they avoid overt homosexuality in animation is it restricts what countries they can sell the series to. Comics don't have that kind of distribution, so it's not so much of an issue. However, the idea there's be sex is ridiculous, since there would still be limits due to Nickelodeon’s interest written into the contract.
As to Dark Horse being dark & gritty, they publish a variety of stuff, especially in book form. For instance.