Even if the Discovery writers do consider it canon, it's never referenced in any of the mod's content except in biographies about SCRA leaders that no one knows about anyway. For all intents and purposes, you could consider it not canon and it would have no effect on how you played in the servers. I personally don't consider the existence of Sol Nomads to be canon in Discovery and I probably never will until the SCRA goes public with its knowledge. I really hope it doesn't do this though. Even though the Nomad faction has tried to explain the existence of Sol Nomads, I find the explanations to be really inadequate, meaning that I'd consider the SCRA's admission of the events in Sol to be a validation of something that didn't and still doesn't make sense in the lore.
The whole eight sleeper ships thing I find much more believable though (there was some controversy years ago about whether or not this deserved to be included in the mod). First of all, it's actually referenced in the original game and its inclusion doesn't open any significant plot holes.
Carlos Rivera: Corsair Brotherhood Pirate - Retired, shifted to Tripoli Shipyard's Research and Development engineering teams Anthony Cameron: Guild Core Bounty Hunter - Killed in Action, committed suicide after being trapped in Omicron Minor following its destruction Juan Ruiz: Outcast Ghost of Razgriz Pirate - Killed in Action, killed by the Sirius Coalition Revolutionary Army during Bretonian piracy raid Michael Winchester: Liberty Security Force Agent - Missing in Action, likely killed during Rheinland espionage mission or trapped in Rheinland Space Eric McCormick: Order Pilot - Retired, shifted to planetside training of new recruits