Usage of 'Only'

Do you feel any difference if we place emphasis on different words like

This is only for me.

This is for me only.

This is only for employees.

This is for employees only.

I think that there is some difference because only is a focusing word but as a non native English speaker, it is not almost possible to figure them out. Please help me again. Thank you so much.

P.S Can I also say, "This is for only me"and "This is for only employees" for the same meaning?

The second of each pair sounds a bit more formal to me.

The answer to your postscript is NO.

Rover

Thank you, and can I ask one more thing? Whether only focuses on me or for me behind, there is not much difference in meaning, right? Please help me out and thank you so much again.

Right—there is not much difference in meaning – if any.