Sorry to hear about your problems. I can't speak to the leaf spring, but I want to let you know something about the grey water line. On the 27RKSS, that line runs very close to the spring shackle bolt. I now have had two times that this bolt has worn a hole in that line, and I didn't have a spring problem. I am currently in negotiation with the dealer to reroute that line. From experience I know if the line is not relocated it will happen again. Good luck with your repairs.
Steve and Marlene and 2 Furry Kids. LB (Maltese) Rocky (Border Terrier)
2013 Coachmen Catalina 25RKS 2006 Nissan Titan Crew Cab