I'd say so... my only concern is the stains use to make the decoration underneath the glaze. However, since they are covered fully in glaze, they will be fine.
In terms of glaze, I would watch out for items that were made about 20 years ago. These have heavy metals in them from time to time and can be toxic to even humans. There was a big recall on them and you can't really find them anymore.
In short, yes. It's fine. I just made some cups using a stoneware clay base and have just glazed them. I plan on using some of them in outdoor buckets/tanks I'm going to set up this summer.