small snacks yes, however, i don’t know why they wouldn’t be able to just grab food from the pantry. we’d definitely have to have conversations about keeping their room clean and making sure to properly dispose of crumbs and wrappers so we can avoid bugs!
a small pet like a rabbit or hamster?
if the bedroom had good ventilation! 
however, in the case of a rabbit, it would be best for the bunny to stay outside/close to outside so it has lots of room.
a dog or cat sleeping in their room?
OF COURSE!! there is nothing better then to cuddle with a dog or cat while going to sleep.
a bookshelf? (thats really ordinary but i can’t think of anything else)
Of course! A bookshelf will be in their room until they request for it to be taken out as reading is heavily encouraged in the home.
[name_m]Art[/name_m] supplies? Such as paint, oil pastels, pottery, etc.
probably only crayons until the age of 8 or 9. after that point as long as they are careful not to stain walls or the carpet it is completely fine!
a vanity?
Absolutely, but especially for girls.
a big walk-in closet?
yes! i have a fairly big walk-in closet and i love it 
a mini fridge?
Yes, this has been one of the things I’ve always wanted and always found cool but never bothered to actually buy because I knew it was useless compared to a regular fridge we already had. But of course as long as they kept their room tidy in terms of food.
[name_f]Music[/name_f] speakers?
I wouldn’t allow any weapons in the bedroom, not even if they’re toys. However, when it comes to my children’s room, they have some creative freedom in decorating it. You can find some unusual things in there. For instance, recently, I ordered a beautiful house sign, and it ended up in my son’s room. Of course, I had to take it back because it had sharp edges. Safety is a top priority, even when it comes to decor.
Totally. Not some massive, wild speakers (of course), but a little plug in one would be great. I grew up with a CD player in my room, and I loved it. I still have one, 20 years later! A love of music is so grand…
[name_m]Wall[/name_m] decals?
If they wanted to!
A mini fridge?
I think so. I’ve always wanted to have one.
[name_u]An[/name_u] art station? (i mean an area with like paints, glue, fabric, paper, ribbons, thread, yarn…)
depends on their age! because a younger child would probably make a mess of that! but if they’re older, most likely yes!
a snack station, like just a few snacks and maybe some drinks like water or mini bottles of flavored drinks or juice boxes?
Maybe, as long as they still ate family meals together
A gaming station?
[name_f]My[/name_f] oldest has a gaming station in his room. The youngest hasn’t shown much interest in video games yet. But I would let her if she wanted one.
What about friends for a sleepover?
Depending how responsible they were and who they were hanging out with.
A mini-fridge?
No. There’ll always be food in the kitchen!
A desktop computer?
As someone who has their own computer, probably yes.
A keyboard (like, the mini piano)?
Yeah of course! I love music and grew up with that
A tablet?
Depends on how responsible and trustworthy they are. If I can trust them not to look up inappropriate things or do stuff behind my back then absolutely! But if they break that trust that privilege is gone for a while.
A fish tank?