Anyone able to ID and provide information about this mountain bike? (DK, Club Roost, FSA)
It’s a custom bike. 

It’s a Saracen team M.A.D frame from late 90’s early 00’s 
with as you correctly say dk stem and club roost bars
The Rear Mech looks like Shimano Deore.
The Forks: RST - most likely, Cranks - Gusset pigmy perhaps? And Pedals are Tioga
Shimano Stx RC brake levers
And that looks like a Mavic D521 rim on the rear.

Hope that helps.