Scott Snowden, 37, and Robert Jennings, 50, are accused of killing Thomas Sharkey, 55, his 21 year-old son Thomas junior and eight year-old daughter Bridget at their Helensburgh home on July 24, 2011.
Thomas junior and Bridget died before their father lost his life in Glasgow's Royal Infirmary on July 30 due to his injuries.
The alleged attempted murder of Mr Sharkey's wife Angela - the childen's mother - during the blaze at the Scott Street property, is also included in the charges.
Both accused deny the allegations against them.
Judge Lord Turnbull set a trial for April 30 at the High Court in Edinburgh and is expected to last several weeks.
See this week's Helensburgh Advertiser for the full story and more details on the trial.