Possible molestation reaction :/ It's common, unfortunately. Please have your children examined by a professional. I was one of these children.
It sounds like it's all for the shock appeal with these two. I have commented on this type of topic and few times and I can tell both of you that it is normal. They will eventually grow out of it.
Oh my god! I have searched high and low on the internet for answers!! I am going trough basically the same thing. My 4 year old has been peeing in his closet, in the trash can next to the toilet etc... He took a bowl from the kitchen into our basement and pooped in it! We have NO idea what is going on. I have heard anything from he' stressed to its a normal phase. What do you think is going on?