The Catholic canon has a lot of those, but not all so including just those common to both would still be something in the majority of Christian's Bibles. Not in the canon does not mean valueless or bad so I think a lot of people will still find books not in their denomination's canon of interest and may have read them.

Maybe offer options on which canon? Does not work well with daily format though. OTOH I would like to play more than once a day!

It is difficult. Maybe weighting towards the new testament (i.e. non-random selection) would make it easier? I think a lot of us are more familiar with it.