Does Hyeongoh know that Namsoo is his real brother?
I would assume so since at the end they call each other by the names that their birth parents game them. Also Namsoo calls Hyeongoh "Hyung" at the end which is said by a male to an older male or the speakers older brother because it means brother. Since they are the same age it wouldn't be proper to call him older brother unless he was addressing him as an actual older brother.
Yukine still unaware of his past and Yato still didn't fight his dad