No, I don't find these interchangeable at all. The first one would always mean to me safe from bodily harm. Secure isn't a word I would ever use to express the same idea from the first sentence. Secure could be emotionally, etc. And the word insecure is never used for bodily harm, but rather is an emotional state, more like anxious or unhappy, never a physical state like safecoften means.

The first two are basically synonymous. The third one refers more to a permanent character trait than to a temporary situation, so it is not synonymous.

Hi there, Yes, you can use all three of these interchangeably since all three convey the same meaning.