Red Bean Cream puffs timing and filling
You do need to soak the beans unfortunately, you are not going to get good results without soaking them. There's really no substitute for adzuki beans which would work well in this recipe, I'd go for another type of filling. 

Choux pastry (ie the puff) can be baked ahead of time but is best fresh as it gets soggy easily.You could make the pastry cream the night before, just remember to get it out of the fridge a good half hour or more before piping so it loosens up. If you absolutely have to make everything the night before don't pipe until the morning as your pastry will be very soggy by the time they are eaten.