Outgoing seems ok, would like a bit more money for all of them. I think Beckford has more potential than Jerome, both would only be back up, so little value in both, Mbokani would cost only slightly more than Jerome. Not seen enough of Ben Arfa to be convinced, seems more of an individual talent. Pienaar worked tirelessly for the team, Ben Arfa would have to replace that effort with additional quality to be an improvement.
In some ways I hope that Moyes and his scouting network have a few young attacking players in mind that are players off the radar again. Lukaku the young strong Belgian player was someone I thought may be worth a look, but he is probably unattainable as he has signed a new 5 year deal with Anderlecht. Without European football to offer, I suspect there won't be too many big name players.