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It does seem that there may be a problem with the Tiny friends sand in the US but here in the Uk although not as good as it was it is still safe to use.
Some people use children's play sand which you need to dry out before use in the oven, I use the Rodipet WitteMolen sand (although it's translated as dust it is actually sand!).
If they pee in the sand it tends to clump up so you can easily remove it with a little scoop or something, even if it gets mixed in they don't get wet or smelly from it, the sand absorbs the pee.
The igloo houses aren't ideal really, plastic tends to get a bit humid & they aren't completely dark, a wooden house (plain wood should be painted with Plastikote water based enamel to pee proof it) is the best option.
There aren't many suitable ones in the UK, there's one that's ok but I can't remember the name right now have to have a look for it! Rodipet do some good wooden houses too, the two room granite house is a good size for a dwarf, I'm not so fond of the labyrinth houses personally although some people use them.

ETA the ferplast sin is the wooden house I couldn't remember earlier! It's a bit small but just about big enough for a Russian ham, the door is big though it needs a bendy bridge over the opening. It's easy to put together & paint & the top comes off which is always a bonus. I'm not a fan of houses with little windows as it should be totally dark in there but substrate piled up around it might help or you could glue some lolly sticks over the window with non toxic glue.