I understand that you will need strong passers (at all positions), drivers (probably from 1-3) and good shooters. Does everyone need a good amount of JR with this offense?
Yes, at least for it to be as effective as it is likely to be. Especially at PF and C, you want to have at least 8-9 JR, since those are the positions that will actually shoot a decent percentage from beyond the arc if you do.