I am not familiar with the buddah dome litter boxes. how big are they? As long as they have room to get in and out, can move around comfortably and such, don't see why they wouldn't work. If they think they have found a great hiding spot...that's where they seem to enjoy laying. Good Luck.
Someone else posted a while ago about using one of them for keeping their ducks in at night. The problem I see with it - is the lip at the top of the ramp- I dont know how tall it is- but some ducks may have issues getting over it from on the ramp. being such a confined space- they cant really flap there wings like they sometimes do to help them get over something when walking around. If you have them already..you can try it out - you have nothing to loose- but for those spending money on something- you can find better things for the same price or less.