Okay dokay... again then:
If we want to keep
Argentorate, it seems there was a Celtic settlement at Baden-Baden (the German city on the other side of the border), so we would only have to move it to the other side of the Rhine, 20 kms downstream. The Romans later called it
Aquae, a Celtic name doesn't seem to be known, but we could still call it Aquae. And when someone complains that Aquae was only founded in 80 BC we'll tell him exactly that. For most pre-Roman settlements North of Italy we'll have this problem anyway.
As for
Mogontiacum there was a Celtic town called Altiaia South of Mainz. Altiaia is today called Alzey (so you can see where it is). Altaia and Aquae are closer at each other than Mogontiacum and Argentorate, maybe that's a problem?
Thebes is too close to the mountains? If you mean the Egyptian one, you should just lower the mountains a bit, if you mean the Greek one we could replace it with another city perhaps.
By the way I have to applaud your friend for choosing Gortyn to represent Crete
I always say everyone it was the most powerful
polis on the island during this time frame, but RTR6, RTRVII, RTW, EB, RSII and Rome II have always fielded it's lesser rival Knossos or the rather unimportant Kydonia. I also like having Naxos and Mytilene, hopefully we can keep them
Considering the Nasiotic League was there we might give them to the Greek superfaction?