Yes.
yes
yes you can idk
No citrus fruits for hamsters.
I have 8 Robo Dwarf hamsters and there are 3 situations when I've heard them squeak. 1. They feel threatened by their cage mate - one of the hamsters is playing too rough or one of them simply does not want to play. 2. They object to being handled. 3. Baby robo hamsters insisting that their mum gives them food. Apart from these three situations, they have not squeaked since they've been living alone.
Yes
Room Temperature water
yeah of course they can hamsters can mate with all different hamsters
Anything you like, really. :)
They mate
No
they eat about a plastic spoon full
Only when they are 8 weeks old.