If they were the late Padishah's harem, that's kinda disgusting. Because that means Shuraka's father must have slept with them. The son inhering his father's harem? Even if it's brother's, it's still kinda disgusting. Even if he didn't kicked them out of the palace, he could've keep them without adopting them into his own harem.
You are right here but it's possible that it's the country's custom as we still don't know much about it and everything is for misunderstanding and keeping the readers on edge. Maybe i am wrong but i just don't want to accept that Shuraka slept with these concubines as he already showed how shy and inexperienced he is
Is it possible that Shuraka inherited the harem from his father because most of the concubines are older so maybe they were in the harem already when he was a child