do you think that the AOT/SNK fandom will ever stop talking about Levi and Mikasa being cousins? Frankly, I don't think Hajime has dropped any obvious hints or said something that implied relation between the two, besides the whole "Ackerman" thing.
Hi anon! Technically, they’re (distant) cousins, and it’s canon alright. Isayama didn’t drop any obvious hints about them at first, and that’s precisely how he stoked the Ackerman mystery surrounding Levi and Mikasa starting from chapter 56, when he dropped the Ackerbomb… back then, many believed they could be as close as siblings!
Yet Isayama made it very clear in chapter 65 (less than a year later) and in the databook (2016) that, despite sharing a surname, Levi and Mikasa are third cousins at the closest, which means they could be even more distantly related, and it’s very likely that they’re no more related than many people (from the main bloodline inside the walls) are.
There always will be a part of the fandom that will prefer to stay blind to these facts due to their own shipping preferences or because it makes them uncomfortable - and that’s perfectly okay, to each their own!