The arrival of Andrew Bynum changes everything, especially as far as the Sixers bigs are concerned! Teams have been known to keep at least 2 Centers and typically a third who rides the bench. This is partly due to the salary cap and the fact that there is only one Center and 2 Forwards and 2 Guards. 3+6+6 = 12.
This means that either Hawes, Brown or Allen will have to be traded, probably before the start of training camp. Centers are always in demand, and the Sixers will try to make a deal that will give them another decent Guard or Forward. This is going to be a critical move, since the Sixers will be able to trade an essentially redundant player in order to fill a need and perhaps the free agent with the chops to take us to the next level along with Bynum and our core.
I suspect it will be Brown if the Sixers can get the player they want in return. Hawes could be a serviceable 4 and Lavoy probably isn't valuable enough to get the player the team needs.