Personally I would just buy the ds suspension and a sr
I would not ride a s suspension on the dirt, unless is smooth dirt, been there done that with a friends xu with fx wheels, so same story dirt(dual sport) wheels tires and then street suspension..... You will jello the inside of the forks if you hit anything decently hard, getting any slight air going over bumps, you can literally hear the fluid separating and bubbling. Granted the Showa might take it better than the fast ace, I still wouldn't do it much if at all. I can imagine the s bikes that are I the 450 range would feel like a tank on the dirt and it would be exasperated if you had street style suspension on it.
A 3 brick monolith battery does feel nimble light, slow as piss compared to a fx
I have a 13fx with stock rear, and 14 S suspension on the front of a fx, for a little more reference, that I ride daily.
I've played with basically every model of zeros mostly x platforms adapting different S platform suspensions on most of them. You seem like your after a DSR or a