Two of the men are also accused of planning to murder the governor of Barlinnie prison in Glasgow with a car bomb.
Anton Duffy, 38, Martin Hughes, 35, Paul Sands, 31, and John Gorman, 57, yesterday made their first public appearance in the dock at the High Court in Glasgow.
They are charged with conspiring to murder Adair and Sammy McCrory, once high-profile figures in the loyalist paramilitary organisation. It was also revealed yesterday that Duffy and Gorman were allegedly part of a plan to target the governor of Barlinnie.
In a seven-page indictment, prosecutors say Duffy, Hughes, Sands and Gorman, along with unnamed individuals, plotted to kill Adair and McCrory between 2010 and October last year.
Locations where the plans were allegedly discussed include high-security HMP Shotts and a flat in Old Castle Road in Shawlands, Glasgow.
It is claimed “surveillance and reconnaissance” was carried out on Adair and McCrory. The charge further includes accusations that there were plans “of where and by what means” each man “was to be murdered”.
It is also claimed there was an attempt to obtain firearms and ammunition, and a plan to procure vehicles, number plates and a safe place to later dump them.
Duffy and Gorman are also accused of being involved in a conspiracy to murder Barlinnie governor Derek McGill OBE, between 2012 and last October.
Prosecutors allege “reconnaissance” occurred to find Mr McGill’s home, vehicle and movements.
It is said this was done with the intention that “Derek McGill would be the target of a car bomb or similar attack”.
Duffy, Hughes, Gorman and Sands also face another charge of joining others with the “intention of committing acts of terrorism”. The allegation spans Scotland, Northern Ireland, the Irish Republic and lists a number of prisons.
It includes claims that contact was made with republican movements the Real IRA and the IRA.
The charge alleges there was a plan to identify individuals and premises “to be the target of action” causing serious harm.
Three other men – Craig Convery, 36, Gary Convery, 34, and Gordon Brown, 29 – joined them in the dock yesterday to face allegations linked to the terror plans.
The Converys are accused of directing others to commit serious offences such as drug dealing and possession of firearms.
This includes instructing individuals in the sale and transportation of a number of deadly weapons such as revolvers and rifles. The trio are also accused of possessing an assault rifle at an address in Paisley, Renfrewshire.
Craig Convery faces a final charge under the Proceeds of Crime Act of having £5,660.
Lawyers for all the accused pled not guilty on their behalf.
Judge Lord Boyd ordered the seven to return to court for a two-day hearing in November.