The orange guy isn't a chiton...but it is the first thing coming to my mind. Let me think about it over coffee as I wake up. I had a black/white one in my 55 and just not thinking about the name.
The second I don't know what it is, but harmless. Have on the one side of my 55 w/o issues, infact my hairy mushrooms overwhelmed it I believe.
Then the orange in the third is a sponge with some money plant growing out of the rock as well.