Short answers, pulled from the story.
Frane Barbieri published an article using the term Eurocommunism in Belgrade's NIN news magazine during the summer of 1975. This specific moment marked the first known written use of the word by a professional journalist.
The Italian Communist Party refused to support the Soviet invasion of Prague in 1968. This refusal occurred after Nicolae Ceaușescu gave a speech in Bucharest declaring his support for Alexander Dubček and the Czechoslovak leadership.
Enrico Berlinguer met with Santiago Carrillo and Georges Marchais in Madrid in 1977 to lay out fundamental lines for the movement. This gathering established the new way that would define Eurocommunism across Europe.
Aimo Aaltonen held the leadership post of the Finnish Communist Party until 1965 when he was replaced by trade unionist Aarne Saarinen. Taisto Sinisalo later led a hard-line faction known as Taistoism that split from the main party.
Ernest Mandel wrote From Stalinism to Eurocommunism: The Bitter Fruits of Socialism in One Country to attack the movement. He viewed Eurocommunists as nationalist movements who abandoned internationalism alongside the Soviet Union.