Four Ancient (Roman?) Coins, ID Help Needed

It's always helpful if you can (a) post separate threads for each coin, and (b) either tell us the diameters or include a millimetre ruler in the picture for scale. Nevertheless, here's what I can find.

12 o'clock: late Roman Bronze, SOLI INVICTO COMITI type, looks like Constantine the Great, the mintmark is PL(?) with the (?) being either "N" (London) or "G" (Lyons)

3 o'clock: no idea. By the thickness, I'd guess a late Egyptian tetradrachm, though the portrait looks more Parthian than Roman.

6 o'clock, it's a denarius (or the larger part of one) of Marcus Aurelius, issued under his father before he became emperor. On the reverse are the sacrificial implements used in the pagan Roman temples.

9 o'clock: from the spiky hairdo, it's a dupondius, and the portrait looks similar to the one on the denarius, so it's from around about the same time. Beyond that, I can't say for sure.