Should this be on ASB when this is ratherly myth than actual history?
No, not really. Myth does not mean fiction in the way that this implies. Whether or not there was an actual Romulus and Remus is besides the point to most historians, but there are a number of academics that do not rule out the possibility that something along the lines of the myth happened and got embellished later on with details like being suckled by a wolf.
Instead, the main question is under what circumstances would the remembered history of the Kings of Rome be positioned in such a way that Remus was not killed? Would there have been a break between the two brothers leading to Rome having a sister city led by its first king's brother? Would Remus have become Rome's first King? Would Rome be called Reme (Rema) instead? Could the two brothers coming together result in a Kingship that is by Kinship, since the Roman institution of Kingship had very little to do with ties of blood? Would the Senate remain an advising body to the King, would it develop more power, or would a competition between the Monarch and the Landed Elites result in early Monarchical Populism, as was the case with the emergence of Tyrants in Greece?
That said, the city would never be called Geminiopolis. That's Greek, not Latin. You could possibly spin it that way by using the other foundation myth of Rome with Aeneas of Troy, but that's going to stretch this far thinner than you might think.