They need a heat lamp over them all the time (including overnight), but not like a light on in the room with them, if that's what you mean. They should have access to food and water at all times at this age. Will you be gone for 8-10 hours somewhere, or do you just mean overnight? For overnight you can just give them a big bowl of food before bedtime (and make sure they have water as well of course so they don't choke on the food). If they run out overnight it's ok, they are fine for a few hours. Make sure they cannot get into their water and get all wet though, then they will chill overnight which can kill them.
Yeah, you can just leave the bowl of food in there for them when you go to bed and they can eat it until it's gone. Then they can wait for you to wake up to give them more. They will be ok. After all, momma duck does not take her ducklings out at night to forage for food.
New babies should have access to food and water 24/7.
No lighting needed at night. I never use any kind of light bulb for heat, I use a ceramic heat emitter. Screws in to your heat lamp socket just like the bulb but does not give off light, only heat, so you can leave it on around the clock.
I stocked up on some 100-watt incandescent bulbs before they disappeared from the store shelves. Now I just use 60-watt incandescents for the heat. That will give them any light they need, too. Once they get old enough to where they don't need as much heat, then I use LED bulbs. However, by that time, they may not need a constant light source, too, so it just depends on what I wanted to do (eg some times I got home late and I would still like them to eat a little bit before calling it a night, so I leave the light on for a bit)