Should I talk about my PhD acceptance in follow up email to potential advisor in different school
No.  You will appear to be threatening to go elsewhere if they do not act on your application soon.  People may react to such (perceived) threats by saying, "Don't let the door hit you on the way out."

If the other institution has a deadline by which you must accept their offer, tell your chosen school, "I really want to come to [chosen school] but other factors require me to make a decision by [week before deadline date.]  Is it possible you could help with that?"