رضا: well in all respects رضا those sentences look foreign. I guess IF You had to write it out with the adverb that you chose.. I would say..

1) In what could loosely be called your life, you've made a living watching others.

and

3)In what could be loosely called your life, you've made a living watching others.

but I don't think a scholar would include the word loosely in the sentence.

In what could be called your life, you've made a living watching others.

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and in your second example none of the sentences make sense..

He may have gone out. would be the correct way of expressing this..

May and probably are different words, however they are being used the same .. Now.. if you switch and use probably your sentence would look like this..

He probably has gone out.

Hopefully I haven't confused ya..