1) It can be a bit smelly with a dry bucket but you can use a deodorising disk which helps. It's really not all that bad though.
2) It's not harder to get the business off. Microfleece liners are brilliant (or you can get flushable ones if you're not into washing them but really it's not that bad) Sometimes I give them a little rinse.
3) I haven't had mildew problems though I don't live in Qld it has been unusually humid down here of late.

I did do the soaking nappy thing with my first child and it was smelly so I don't think you can get away from the smell either way.