Well, ADFs work well with bettas in most cases. The only way they don't work is if you have an overly aggressive little gal or guy. I've been reading up on ADFs a lot since I might upgrade my 5 gallon to a 20 gallon and add a few frogs with my betta and snail. However, ADFs are, from what I've read, entirely aquatic and I've never heard of them going on land.
I love newts/salamanders; I had quite a few when I was a kid.
I saw a picture recently of this lovely paludarium. Someone took natural gravel, piled it high for the land part, and sloped it downward to meet a bed of sand. They scattered some pebbles/gravel here and there to blend the sand and gravel. They filled the sandy part with water and added platies. It was so lovely. There was a lot of java fern in the sand part. I think java fern can live partially out of the water, if I'm not mistaken.