I can't write a lot right now because i am on ny cellphone right now.

The political situation in Brazil was from stable.

There were a lot of reasons why it ended, the main ones being the abolition of slavery, Don Pedro II interfering with the church, the military wanting to express their opinion on the press, the middle class wanting to participate in the polits and the land owners wanting more power.

Don Pedro II was losing political power and was being secluded from various polical decisions from various sectors of the government.

The republican overthrow happened overnight by marshall Deodoro da Fonseca firing the ministers board and signing the proclamation manifest.

Edit: There were/are no movements trying to restore the monarchy, the closest would be the military dictatorship during 1964-1985