If you are going manual hubs as well as a non ADD diff it it possible to keep your current ecu, however if you get a the ecu for a 4x4 5 speed you will avoid a whole lot of wiring work there still may be some though.
When I did my 5 speed swap I used the engine wiring harness from my donor truck because mine was corroded and chaffed through in multiple spots. Because of this I used the ecu from the donor truck and had zero wiring to mess with. I do not have the safety switches for the clutch so it is like an older generation truck where it could be started in gear, I'm yet to have an issue with this. If you have any questions feel free to ask!
Way to finally get a pic up! I dig the blacked out look! What did you use to do the grill and bumpers?