They include Bianca Rojas-Latraverse, a former girlfriend of Duhamel's.
The other person who will be staying behind bars is John-Stephen Clark-Lemay.
Judge Pierre Belisle had harsh words for the 20-year-old Rojas-Latraverse on Tuesday, saying she took advantage of her relationship with Duhamel to play a key role in the planned attack.
Belisle said he couldn't release Clark-Lemay because of his criminal record, his lifestyle and his problems with alcohol.
The judge did allow Anthony Bourque to be freed pending the beginning of his trial next month.
The three face various charges, including conspiracy, armed robbery, assault and break and enter.
Belisle said Bourque has clear plans and is not a flight risk.
A fourth person arrested in the case had already been freed pending further court proceedings.
Duhamel was beaten up at his Montreal-area residence last Dec. 21.
He was robbed of cash, a Rolex watch as well as a bracelet he won for capturing the World Series of Poker in 2010.
Police have recovered the watch but not the bracelet.