Some information from CSS
Vargas is alive by 1962, aged 79, he's the president of the PTB but most of the administrative work is done by others, with him only interfering when necessary. The PTB is completely dependent on him, especially their candidate João Goulart. The PSD party of Juscelino Kubitschek and Tancredo Neves are also under his control, but they have a more western-aligned outlook and so his hold is smaller, especially since the only person that can rivalize Vargas in popularity is Juscelino. The PSP, party of the governor Adhemar de Barros in São Paulo and the underdog party for 1965 is quite independent, but Vargas son
Getúlio Vargas Jr leads a Getulist branch of that party.
To summon it up, the only party free from Vargas interference is the UDN. Vargas will die somewhere on the late 1960s since he's obese, like,
very obese.
Plínio Salgado got exiled in Portugal after a attempted coup in 1955, the coup (that happened OTLand was aborted OTL too) tried to prevent JK from gaining power. Salgado was friendly to JK but the fascist wing of the party caused infighting paralyzing it during the coup and he got exiled to Salazarist Portugal after the backlash (thanks in part for the CIA interference). He's classified as fascist under the integralist subideology, while there is a openly fascist wing of the party under the only integralist brazilian president to ever rule the country OTL. Salgado caused so much chaos during his development that we considered removing him from the 1970 election, but went back on it, partly because he's a house of contradictions, he was friendly to Kennedy, supported the postdam conference, hated nazism, wanted to break up fascist italy into pre unification states, etc. The best way to describe him is a more pro NPP-C Salazar.
The two most "dangerous" candidates that can take power by ballot are Jânio Quadros and Adhemar de Barros, let's start with Quadros
Quadros was a political phenomenon OTL, he was a incompetent but highly cultured individual that managed to surf on the wave of anti corruption and use his charisma to get the presidency, and then screwed up everything after it, his whole government was like a sadistic joke that never ended and dragged on and on (for seven months) until he resigned expecting the people to protest to keep him in power, but instead they commemorated he was gone. Quadros is a conservative and will try to prevent moral decay (not as harshly or efficiently as Salgado), but he lacks the skill for most of what he plans for Brazil and so his lusotropicalist christian conservative ideal is far from being likely
Adhemar de Barros (someone stole his picture, probably him), is the least likely candidate to win in 1965, but also the one that will cause the greatest impact, he knows what he wants and where he's going, and he might assume a level of control similar to what Vargas had 20 years before or Thatcher at the end of his campaign in TNO, not through repression or executive powers, but through political connections that go so deep crossing the borders of public, private, political, economical, national and foreign groups.
In general all figures can succed on their plans or fail, we won't tell you which one is "the best", just get the figure you want and have fun. Many others can take power, elected or not, but these are the most interesting for now. Juscelino is basically a revival of his 55-60 government, Jango is his OTL government (he's the most likely to be couped), and then we got the generals, about five of them.