Well done!
Another thing that deserves mention is that the civil war actually started years before the Nazis left. The communists had been attacking not only the Nazis, but also right-wing resistance groups (EDES, PAO, EKKA)! The Brits actually brokered a ceasefire in early 1944, which the communists broke 2 months later by murdering resistance leader Psarros (https://en.wikipedia.org/wiki/Dimitrios_Psarros).
There is no assuming involved; they didn't simply "want" a violent take over, they actually tried to do it and lost.
This is not really the case. Two "groups" were to be left armed (and transformed into a national army): the 3rd Greek Mountain Brigade and the Sacred Band. Both groups were formed by the Greek government in exile, and were under the control of the Greek government. Both groups fought in battles against the Nazis. There is no question of collaboration among them.
As for the cops I'm sure there were collaborationists in their ranks, and obviously firing on the crowd was both wrong and a massive mistake. But this is no justification for anything the communists did.
One cannot have been a communist in Europe in these times without being in an active supporter of Stalin. The ComIntern and essentially all European communist parties were under strict control of Moscow/Stalin. Those who opposed Stalin typically faced a violent end.
Of course after Stalin's death and the concommitant weakening of communist power, most communists active during Stalin's times lied about their involvement.
Mark Mazower's "Inside Hitler's Greece: The Experience of Occupation 1941-44" is an excellent book on the subject.