I bought the arena yesterday afternoon for $25, here's my set up.... which I believe is pretty accurate.
Balcony (from left to right) ->
Boba Fett, Pilot Jango, Mace Windu (w/ saber to Jango's throat), Mace Windu, Nute Gunray, Lott Dodd (I've got Rune Haako from Ep1 standing in, as I have yet to see a Lott in stores)
Arena Floor (no order) ->
About 5 battle droids (most are oom9's, actually, which is inaccurate, but I haven't found any reds either)
Ep1 Obi-Wan (face down to simulate Jedi casulty)
the female w/ striped lekku (forgot name)
Need to add once I find them :
Aayla Secura, Coleman Trebor (I'll have him on ground I guess), Lott Dod, Poggle (I'll have him flying away or somethin as the balcony is full), Wat Tambor (again, I'll figure something out w/ his placement)...