I think we're rather alone
1. Vargas never taker a power (1930)
Whatever happens, the República Velha would not have survived. The whole system of coronelismo and café com leite was challenged by the middle-class liberals, the Communists, the fascist Integralists. Then you had the depression. A military coup was quite inevitable by 1929/1930.
2. Quadros did not resign (1961)
Not sure. The PTB was only the third party in Congress and his pro-Soviet bloc policies prevented the UDN from supporting him. He would have been largely powerless, until the 1962 congressional elections... and in RL the PTB didn't have a majority there either.
3. No coup, Goulart allowed to complete his term (1964)
I think that's pretty unlikely, the military was too right-wing for such a leftist. Anyways, nothing would've happened. His agrarian reform and oil nationalization couldn't have been done.
4. Both Geisel and Figueiredo didn't started "opening" and military regime remained at Médici stage
Geisel had it in him to open the regime, stemming from his legalist tradition. I think he saw it as a duty, in a way.
5. Neved did not die, no Sarney administration (1985)
Hard to say how Neves would have been. We have little stuff to give an indication of how he would have been. I suspect that he would still be hurt by the economic problems that Sarney faced.
7. Collor not impeached (1992)
He would still be unpopular due to the allegations of corruption and he'd be remembered as a crappy President.
8. Itamar Franco allowed to run again and reelected (no suprise, he enjoyed 80+ approval job ranting), no Carodoso (1994)
Franco would probably have been a better President than Cardoso, but with largely the same policies (remember, Cardoso was Franco's Finance Minister)