I also feel that Majority chances are that they would be overnight , day time uday not needed as of now. tejas and shat and jan shatabdi are there to fill that need. AFAIK , overnight uday would also be chair car but flight like leg space and seat inclination would be provided.
as far as bza - sbc route is concerned , it has great potential but TT should be kept tight so that it completes the journey in 10 hrs to avoid passenger fatigue. ypr duronto currently takes 11.5 hrs so it is quite possible.