The "message center" is just a conglomeration of idiot lights. You'll need to have a signal sent to it for each of the desired outputs. I have no idea what type of signal. You'll have to research that. Could be a simple continuity situation or some level of voltage. The fuel level, for example, works at the dash gauge level via change in ohms resistance as metered by the float assembly in the tank. All the various manufacturers use varying different ohms ranges. I'd guess you'd need to get a sender to swap into your truck's tank that worked on the Ford ohms range. Even then not sure how it actual is wired at that piece.
Systems that indicate a burned out light bulb also use different means to signal the bulb is bad. Lack of current draw. Open circuit disrupted by a "popped" filament. Or other means. You'll need to find out what Ford was using when that piece was in production and then modify the truck wiring harness at each bulb socket to provide the appropriate signal back to the message center.
Easiest one is likely the low washer fluid piece. Just need a float that signals when it drops to certain level. Then again, you still need to find out what that signal to the center needs to be.
I have to believe you've chosen to bite off a whole lot more than you expected.
