Is it okay to keep a giant rabbit in a cage overnight and while I'm away as long as it is really big?? :/ x?

You would need a huge cage for a giant rabbit. Rabbits can make great house pets but do like to chew so need to make sure the house is rabbit proof . They will chew things like walls , wires and carpet etc. And they can live happily with cats but you do need to be careful not only can a cat hurt a rabbit rabbits can seriously hurt cats. They have a serious back leg kick.