Of the footballers you listed, only Lukaku is a forward.
Kerem isn't an out-and-out striker; he's a winger. The others are midfielders.
Also, İsmail Yüksek isn't a regular starter for the team. You wrote this to criticize, but its not a particularly valid criticism.
Kerem is not a real striker, but if necessary he can certainly be moved around and provide what a striker normally provides. In addition to this, Lukaku is the only real striker, but given his physical form and the injury from which he is trying to recover, it will be difficult for him to quickly achieve ownership.
Considering his age, Lukaku will never be the player he once was.
The Fenerbahçe management made this move just to show the fans, "Look, we brought in Lukaku," yet they were late in doing so.
Lukaku has yet to score a goal in a Fenerbahçe jersey.
His physical condition is abysmal.
Sidiki Sherif was the right fit for this team, but unfortunately, Turkish clubs tend to pursue these kinds of transfers because they want immediate results.