1. It does not absorb pee well so you may get odour issues. You could give it a go I suppose but I’m a little wary myself. You could opt for wood pellets, they are very affordable at 3-4 euros per 10 kg. Which type of pellets are you feeding? If you are feeding something expensive such as Science Selective or Beaphar (30-40 euros per 10kg) you could look into Hopefarms Supertrio (18 euros per 15kg), which is also a nice quality of pellets.

2. You don’t need a hutch if you have a pen. Hidey houses are enough. C: If you don’t want a pen and only have a hutch, I’m not sure if there are any indoor ones commercially.

3. I believe 2 small bunnies need at least 2 square meters on a single level.

P.s. Cheap hay can be a little dusty, I believe more expensive hay less so. You could shake it out outside and then store it in a box or something. Also the dustyness is only there while you refresh the hay, so it shouldn’t be dusty all day. Honestly, if your boyfriend can live with the dust of a dog, a cat and a rabbit, hay should not be a huge issue for him.

I’m not sure about the prices, but it would definitely create more wastage to use hay as bedding as like what Daisy mentioned, they don’t absorb well and will need to be changed super frequently not just because of odour, but also because your bunnies would be sitting in wet hay and that’s not good for them.

I always recommend wood pellets + litter box with a grate. With one Netherland Dwarf bunny, his waste can sit there for three days and still wouldn’t smell bad (until I open the grate to dump it out lol). I change it every 2-3 days, and you don’t need a lot of litter because they are so absorbent.

For bedding, I would recommend buying a couple of fleeces. These can line the hutch, and can be alternated and washed. Then it’s just a one off cost of buying them. Then, you will also need litter for the litter trays. Hay can work, but it’s less absorbant than proper litter. I use paper pellets, but non-clumping wood pellets are also fine, and are generally cheaper.

Generally, it’s better to have a hutch that is on the ground, so that the rabbits can get in and out of it themselves. It can make them scared of you if you’re constantly picking them up and chasing them around to get them back in. Most commercially sold hutches aren’t big enough for one rabbit, let alone two. I would suggest something like a couple of X pens, which you could use to create a home corner for them.

Here’s some size guidelines for guidance:
http://www.therabbithouse.com/guide_size.asp

Hay is the most essential part of a rabbits diet. It’s not unhealthy for humans, and not feeding it to rabbits isn’t an option.

Hay is dried grass. It’s dusty from pollen and airborne particles, just like normal, outdoor air, so it is not unhealthy to humans. Just as humans can have allergies to grass and pollen, they can have allergies to certain types of hay. It’s not healthy vs unhealthy.

I’ve always used a layer of Carefresh litter topped with a layer of hay for my rabbits’ litterbox. Interestingly, they seem to be finding that a very comfortable space for sleeping lately…