What is the width of the 2 inch rollers?

Two inches is the width inside the roller, which is large for long hair. I have a shorter haircut, so I use the 3/4 inch for the bangs and 1 inch for the rest of my hair.

Can you wear these to bed? Are they comfortable to sleep in for the entire night?

Unless you sleep in a chair and don’t move your head much maybe but these are primarily plastic so they don’t have give so it wouldn’t be comfortable and depending how you secure them in I would worry that sleeping on them could potentially pull on your hair. I don’t reccomend sleeping in them however once you blow dry and put them in I walk around the house in them for approx 10-15 minutes and take them out with lots of volume which is what I go for

are they able to be slept in without pulling hair?

i was able to but i only used them on top

Are these ceramic curlers as lightweight as the aluminum?

I’ve never used aluminum curlers, but these ceramic curlers are very light weight. A hairdresser recommended these curlers and I get a lot more body in my hairstyle than just using a brush and hairdryer.