Is it fine to not give my beagle water after 7:30 PM?
he eats dinner at 7:00 PM
Seems like a long time without water to me. Personally, I hate being thirsty. Are you trying to housebreak him? I would take him fot a short walk before bedtime if I was you.
Sure, provided you give him water 1st thing in the am
depending on when he goes to bed.