I don't see any chance of extension of 14123/24 to FBD for a veru simple reason. Utsarg Exp is allready extended and its timimg will clash with 14123/24 both sides as there is a gap of just 20-25 mins. Still INR can make any unusual/foolish decision without taking into consideration the need of the passengers or financial viability. To extend trains just due to shortage of servicing facility in yard is not financialy viable.
Though a train is needed around 9-10 pm from Kanpur towards FBD or Kasganj as there is no connectivity after 7 pm.