The brackets would need to be attached at the studs of the wall (assuming these are standard drywall and stud walls). Otherwise, the whole thing will come tumbling down, taking part of the wall with it
Yeah, we're going to attach it to the studs 
The weight rating on the brackets only tell you that the brackets won't break.
How would I know if they can hold the detolf + the bedding etc, then?
If you are worried about the hamster escaping and falling (and it's a risk with shorter cages like the Detolf), consider putting something soft to land on underneath.
I'm going to put a soft rug underneath, but do you think I would need something more cushiony?
Keep in mind that other natural disasters can be an issue (tornadoes, hurricanes, etc.).
We don't have many natural disasters here, so I'm not very worried about that 
I could possibly use a shelf that has legs on the ground, not sure if that'd be sturdier? But my room is pretty small so I would really like to have it so that I can have space underneath.
Edited by CallaTheHam, 02 March 2022 - 01:49 PM.