Gusmao escaped unharmed from an ambush on his convoy later the same day.
The defendants were mostly former soldiers and police who became rebels and fugitives after factional rivalries within East Timor's security forces erupted into violence in 2006, killing dozens and toppling the then government.
Australian woman acquitted
Angelita Pires, an Australian-East Timorese citizen, was among those acquitted.
She was the girlfriend of Major Alfredo Reinado, the rebel leader who was fatally shot by the president's guards during the first attack.
"Today is the most important day of my life. I have rightfully regained my freedom," Pires said after judges dismissed the prosecutors' argument that she was a key player in the plot as she made several trips to the northern Australian city of Darwin to raise funds for the rebels.
The prosecution said that Pires had encouraged the attack and had said it should be made to look like a coup.
She faced up to 20 years in prison if convicted.
Lieutenant Gastao Salsinha, who replaced Reinado as leader and commanded the failed attack on Gusmao, was sentenced to 16 years in prison.
The shortest sentence was nine years and four months.
The defendants are mostly army and police deserters who turned rebels after factional rivalries within East Timor's security forces erupted into violence in 2006, killing dozens and toppling the then government.
The rebel group comprising some 600 soldiers complained that they had been discriminated against because they were from the western part of East Timor
Damien Kingsbury, a professor of international studies at Deakin University in Australia, said the trial is the greatest test of East Timor's judiciary since the territory separated from Indonesia in 1999, gaining formal independence in 2002.
He said that whatever the outcome, East Timor's justice system will be criticised because it is widely perceived as incompetent, but not corrupt.
"I don't think the reaction will go beyond a bit of active debate," he said, disagreeing with predictions that the verdicts could spark violence in the capital.