2 and 5 are correct.
I think the others may be used in slangy or informal spoken English. They are really shortened forms of
"Stare at him -- that's what I did."
"I stared at him; that was what I did."
I think it would be perfectly possible and not particularly remarkable to hear (in colloquial conversation)
> "Stare at him's what I did."
> "Stared at him's all I did."
The speaker is making a noun out of "stare at" and using it as the subject of the sentence.