2) Q400 CDU :
Pages: weight of the plane - Fuel - Passengers -pussback?
and for all the pages like in the real plane it is planned that it is modeled?
Just like you I've flown the Majestic Q400 (a lot!) and the latest AFS2 beta brings enough options to the Q400 to forget about P3D and the Majestic Q400, not because everything is working in AFS2 right now but because the things that I like to use are modelled now (after modding the tmd to cold and dark). I am sure that in the future weight, fuel, pax, etc. will be added to the FMS too. (The main thing I am looking forward to right now are Direct to's and a working VNAV page).
One funny thing though: you mention pushback. But in that case you aren't talking about a realistic simulation of the real plane anymore but about a Majestic feature that had been added for convenience: in the real world you don't use the FSM for pushback! I do hope the upcoming ATC will open the door to realistic real world pushbacks: that would surely be a lot better than simulating another simulation by using the FMS for pushbacks.