I have 2 male rabbits who happily play together during the day but won't share a hutch at night so they each have a big double story hutch.
Bun 1 - has a small cat bed pushed into the enclosed sleep area, I put his heat pad in that at night, the top of the hutch has a deep bed of hay, downstairs has a thick layer of shavings and one half of it is packed from floor to ceiling with straw, he burrows into it.
Bun 2 - his hutch is technically 3 floors, on the very top shelf he has his food, under that is the enclosed bedding area which is full of straw which he burrows into and that's where his heat pad goes, the rest of the top floor has a deep bed of hay, downstairs he has deep shavings and straw.
They both have insulating stuff on the top and sides of the hutches, a babys cot duvet on the roof, a fleece blanket that covers the back, top and front of hutch and a waterproof cover that goes over the whole hutch.
I use old socks to cover the water bottles.
I also have a house rabbit, he has the run of the house when we are there and sleeps cuddled uup to the dog but over night and when we are out he stays in his cage (its one of those that has a plastic base and metal cage lid) I worry about him getting cold as our kitchen gets
very chilly so he has 2 fleeces on the base, a fur lined teepee where he sleeps, a huge fleecy throw over the top which comes down the sides so only the front is visable and he also has a heat pad
They all seem happy so I must be doing something right, they are a stroppy bunch when they have a problem