My preferences are for Yabu to be elsewhere. I have no problem packaging him and a pick for someone on the late part of their rookie deal that still can grow but can contribute some now. Yabu is useless.
In that scenario, I have no problem bringing in 2 rookies for roster slots 14 and 15. But if Yabu remains, I only want one rookie on the team. Those last three slots should be for players you don't expect to contribute so best use it on players to develop that you can have regularly in Maine.
I think Williams is one of those players so the other two can be two rookies or Yabu and one rookie. I in no way want to see Yabu, Williams and 3 rookies, plus a couple of two way players on this team next year.