I have played a couple racing games on Xbox that let my phone show dashboard with gauges was wondering if that would work on flight sim
Hypothetically the functionality exists within the sim code to do this yes.
It certainly works in the PC version.
I currently have several applications communicating via network (and have indeed run a moving map on a tablet over wifi)
I guess asobo/Microsoft will have to make sure the correct ports are open and then any number of external apps ought to work via SimConnect.