Is Laenor going to be written out? He's supposed to be Rhaenyra's first husband. He would be Corlys' son, but the actor playing Corlys doesn't look that old, although I guess it could work. It would mean the three kids of Rhaenyra would be mixed, but since there were rumors her children were fathered by Harwin Strong (who I guess would be a white guy?) then I guess they wouldn't be mixed? And the rumors would not be rumors then. Also it is implied Laenor was gay.
I guess they could cut out the "rumors his children were fathered by another man" entirely, in that case Jacaerys, Lucerys, and Joffrey would all be mixed kids. Jacaerys is pretty important as he is key to the Pact of Ice & Fire which has big ties to the whole A Song of Ice & Fire plot, so I doubt they would write him out.
Maybe they'll make it that the mixed lineage is the reason so much was done to prevent Rhaenyra's line from ruling. Would be more interesting, and I feel it works well for television story-telling, it makes things more obvious.